Trichlorosilane purification system and method in polycrystalline silicon production

Abstract

The invention discloses a system and a method for purifying trichlorosilane in polycrystalline silicon production, the system comprises: an adsorption device filled with an adsorbent and used for introducing trichlorosilane in polycrystalline silicon production for adsorption treatment to obtain a first liquid; the complexation reaction device is connected with the adsorption device and is used for introducing a liquid complexing agent to be mixed with the first liquid for complexation reaction to obtain second liquid; and the rectifying device is connected with the complexing device and is used for rectifying the second liquid to obtain purified trichlorosilane. According to the trichlorosilane purification system and method in polycrystalline silicon production, a purification process combining adsorption, complexation reaction and rectification is adopted, impurities with low boiling points such as boron and phosphorus are removed through adsorption, a complexing agent is used for carrying out complexation reaction with boron, phosphorus and metal impurities to generate a high-boiling-point complex, and the trichlorosilane is purified. And boron and phosphorus impurities and high-boiling-point metal impurities are further removed through rectification.

Description

Technical Field

[0001] The invention belongs to the technical field of polysilicon production, and in particular relates to a trichlorosilane purification system and method in polysilicon production. Background Art

[0002] Trichlorosilane (SiHCl3) is an important intermediate for the synthesis of silicon-based materials, and related products are used in photovoltaics, semiconductors, metal ceramics, surface treatment agents, inorganic filled plastics, tackifiers, sealants and other fields. At present, the processes for removing impurities from trichlorosilane (including donor impurities, acceptor impurities, carbon, etc.) mainly include distillation, reaction and adsorption. The traditional distillation method uses the relative volatility difference between trichlorosilane and impurities to achieve separation. The technology is relatively mature. Impurities such as iron and manganese compounds can be directly removed by distillation. However, the boiling points of some impurity compounds (such as BCl3, PCl3, PCl5) in the distillation process are close to those of the product trichlorosilane, and it is difficult to remove them directly by distillation. Other technologies must be combined to achieve deep removal of impurities. US5445742A reported the adsorption capacity of high-silicon zeolite for hydrocarbon compounds. The saturated hydrocarbon content of chlorosilane samples was reduced by 94.2%, the unsaturated hydrocarbon content was reduced by 99.6%, and the chlorinated hydrocarbon content was reduced by 50%. US

[0003] 4713230A reported the use of a fixed bed of silica to remove boron impurities from trichlorosilane, with a removal rate of 99.2% for boron impurities in the sample. US 4224040A reported the use of an acidic cationic resin containing aluminum trifluoride or anhydrous magnesium chloride to adsorb phosphorus, arsenic and antimony compounds, with an adsorption rate of 99% for boron impurities and 99.6% for phosphorus impurities. At present, trichlorosilane adsorption and impurity removal technology is widely used in the preparation of photovoltaic-grade products, mainly for removing ppm-level impurities. However, it is still very difficult to separate ppb or even ppt-level trace impurities. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a trichlorosilane purification system and method in polysilicon production in view of the above-mentioned deficiencies in the prior art. In order to solve the many deficiencies in the existing trichlorosilane impurity removal process, the present invention combines adsorption, complexation and distillation to deeply remove trace boron impurities, phosphorus impurities, carbon impurities and metal impurities in trichlorosilane.

[0005] The technical solution adopted to solve the technical problem of the present invention is to provide a trichlorosilane purification system in polysilicon production, comprising:

[0006] An adsorption device filled with an adsorbent, the adsorption device is used to pass trichlorosilane in polysilicon production for adsorption treatment to obtain a first liquid;

[0007] A complexing reaction device is connected to the adsorption device, and is used to introduce a liquid complexing agent to mix with the first liquid to perform a complexing reaction to obtain a second liquid;

[0008] The distillation device is connected to the complexing device, and is used for distilling the second liquid to obtain purified trichlorosilane.

[0009] Preferably, the adsorption device comprises: a first input pipeline, a flow controller, an adsorption column,

[0010] The first input pipeline is connected to the adsorption column, the flow controller is arranged on the first input pipeline, the first input pipeline is used to input trichlorosilane in polysilicon production, and the adsorption column is connected to the complex reaction device.

[0011] Preferably, the complex reaction device comprises: a second input pipeline, a booster pump, and a static mixer.

[0012] The second input pipeline is connected with the static mixer, the booster pump is arranged on the second input pipeline, the second input pipeline is used for the liquid complexing agent, and the static mixer is connected with the adsorption device.

[0013] Preferably, the distillation device comprises: a distillation tower, a tower top heat exchanger, a tower top receiving tank, a circulation pump, a reboiler, a tower bottom heat exchanger and a tower bottom receiving tank.

[0014] The top heat exchanger is connected to the top of the distillation tower, the top receiving tank is connected to the top heat exchanger, the circulation pump inlet is connected to the top receiving tank, the circulation pump outlet is connected to the top of the distillation tower, and the inlet of the distillation tower is connected to the complexing device; the reboiler is connected to the bottom of the distillation tower, the bottom heat exchanger is connected to the reboiler, and the bottom receiving tank is connected to the bottom heat exchanger.

[0015] Preferably, the trichlorosilane purification system in the polysilicon production further comprises a product storage tank.

[0016] The product storage tank is connected to the tower top receiving tank, and / or the product storage tank is connected to the outlet of the adsorption device.

[0017] The present invention also provides a method for purifying trichlorosilane in polysilicon production using the above system, comprising the following steps:

[0018] Passing trichlorosilane produced in polysilicon production into an adsorption device, and performing adsorption treatment through an adsorbent filled in the adsorption device to obtain a first liquid;

[0019] Passing a liquid complexing agent into a complexing reaction device to mix with the first liquid entering therein, and performing a complexing reaction to obtain a second liquid;

[0020] The second liquid entering the distillation device is subjected to distillation treatment to obtain purified trichlorosilane.

[0021] Preferably, the flow rate of the flow controller is 10 to 150 kg / h.

[0022] Preferably, the pressure of the adsorption column is 0.5-2 MPa and the temperature is 50-70°C.

[0023] Preferably, the pressure of the booster pump is 1 to 5 MPa.

[0024] Preferably, the pressure of the static mixer is 0.5-2 MPa and the temperature is 50-70°C.

[0025] Preferably, the pressure of the distillation tower is 0.3-0.8 MPa and the temperature is 50-160°C.

[0026] Preferably, the liquid complexing agent is one or more of N,N,N',N'-tetramethylethylenediamine, 1,2-biphenylthioethane, bis(2-dimethylaminoethyl) ether, triphenylsulfur chloride, 3-methoxypropionitrile, diethylene glycol diethyl ether, triethylchlorosilane, tetrahydrothiophene-3-one, tetrahydrothiopyran-4-one, ethylene glycol bis(propionitrile) ether, triisopropylchlorosilane, and ethoxyethyl cyanoacetate.

[0027] Preferably, the adsorbent is one or more of silica gel, activated carbon, molecular sieve, supported molecular sieve, and modified mesoporous silica.

[0028] Preferably, the molecular sieve is any one or more of molecular sieve SBA-15, molecular sieve MCM-41, molecular sieve MCM-48, molecular sieve 5A, molecular sieve 13X, β-type molecular sieve, and Y-type molecular sieve.

[0029] The present invention aims at the problem that trace boron, phosphorus, carbon and metal impurities cannot be deeply and simultaneously removed due to the single impurity removal means in the trichlorosilane purification process. The trichlorosilane purification system and method in the polysilicon production of the present invention adopt a purification process combining adsorption, complex reaction and distillation, remove impurities with low boiling points such as boron and phosphorus by adsorption, use a complexing agent to react with boron, phosphorus and metal impurities to generate a high boiling point complex, and further remove boron and phosphorus impurities and high boiling point metal impurities by distillation; the complexing agent used in the present invention has a complexing effect on boron, phosphorus and metal impurities and does not react with trichlorosilane; the trichlorosilane purification system and method provided by the present invention can realize the simultaneous deep removal of impurity components in trichlorosilane gas, and the removal efficiency of phosphorus impurities is higher than 80.4%, the removal efficiency of boron impurities is higher than 95.6%, the removal efficiency of carbon impurities is higher than 83.1%, and the removal efficiency of metal impurities is higher than 85.7%. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1It is a schematic structural diagram of a trichlorosilane purification system in polysilicon production in Example 2 of the present invention.

[0031] In the figure: 1 - flow controller; 2 - adsorption column; 3 - booster pump; 4 - static mixer; 5 - distillation tower; 6 - tower top heat exchanger; 7 - tower top receiving tank; 8 - circulation pump;

[0032] 9-reboiler; 10-bottom heat exchanger; 11-bottom receiving tank; 12-product storage tank;

[0033] 13 - first input pipeline; 14 - second input pipeline. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0035] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0036] In the description of this patent, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing this patent and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this patent.

[0037] In the description of this patent, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, it can be fixedly connected or set, or it can be detachably connected or set, or connected or set in one piece. For ordinary technicians in this field, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0038] Example 1

[0039] This embodiment provides a trichlorosilane purification system in polysilicon production, comprising:

[0040] An adsorption device filled with an adsorbent, the adsorption device is used to pass trichlorosilane in polysilicon production for adsorption treatment to obtain a first liquid;

[0041] A complexing reaction device is connected to the adsorption device, and is used to introduce a liquid complexing agent to mix with the first liquid to perform a complexing reaction to obtain a second liquid;

[0042] The distillation device is connected to the complexing device, and is used for distilling the second liquid to obtain purified trichlorosilane.

[0043] The present invention also provides a method for purifying trichlorosilane in polysilicon production using the above system, comprising the following steps:

[0044] Passing trichlorosilane produced in polysilicon production into an adsorption device, and performing adsorption treatment through an adsorbent filled in the adsorption device to obtain a first liquid;

[0045] Passing a liquid complexing agent into a complexing reaction device to mix with the first liquid entering therein, and performing a complexing reaction to obtain a second liquid;

[0046] The second liquid entering the distillation device is subjected to distillation treatment to obtain purified trichlorosilane.

[0047] The present invention aims at the problem that trace boron, phosphorus, carbon and metal impurities cannot be deeply and simultaneously removed due to the single impurity removal means in the trichlorosilane purification process. The trichlorosilane purification system and method in polysilicon production of the present invention adopt a purification process combining adsorption, complex reaction and distillation, removes impurities with low boiling points such as boron and phosphorus by adsorption, uses a complexing agent to react with boron, phosphorus and metal impurities to generate a high boiling point complex, and further removes boron and phosphorus impurities and high boiling point metal impurities by distillation; the complexing agent used in the present invention has a complexing effect on boron, phosphorus and metal impurities and does not react with trichlorosilane; the trichlorosilane purification system and method provided by the present invention can realize the simultaneous deep removal of impurity components in trichlorosilane gas.

[0048] Example 2

[0049] like Figure 1 As shown, this embodiment provides a trichlorosilane purification system in polysilicon production, comprising:

[0050] An adsorption device filled with an adsorbent, the adsorption device is used to pass trichlorosilane in polysilicon production for adsorption treatment to obtain a first liquid;

[0051] A complexing reaction device is connected to the adsorption device, and is used to introduce a liquid complexing agent to mix with the first liquid to perform a complexing reaction to obtain a second liquid;

[0052] The distillation device is connected to the complexing device, and is used for distilling the second liquid to obtain purified trichlorosilane.

[0053] Preferably, the adsorption device comprises: a first input pipeline 13, a flow controller 1, an adsorption column 2,

[0054] The first input pipeline 13 is connected to the adsorption column 2, and the flow controller 1 is arranged on the first input pipeline 13. The first input pipeline 13 is used to input trichlorosilane in polysilicon production, and the adsorption column 2 is connected to the complex reaction device. After passing through the flow controller 1, the material enters the adsorption column 2 from the bottom.

[0055] Preferably, the complex reaction device comprises: a second input pipeline 14, a booster pump 3, a static mixer 4,

[0056] The second input pipeline 14 is connected to the static mixer 4, the booster pump 3 is arranged on the second input pipeline 14, the second input pipeline 14 is used for the liquid complexing agent, and the static mixer 4 is connected to the adsorption device. Specifically, the static mixer 4 is connected to the tower top outlet of the adsorption column 2, and the booster pump 3 is connected to the inlet of the static mixer 4.

[0057] Preferably, the distillation device comprises: a distillation tower 5, a tower top heat exchanger 6, a tower top receiving tank 7, a circulation pump 8, a reboiler 9, a tower bottom heat exchanger 10 and a tower bottom receiving tank 11.

[0058] The top heat exchanger 6 is connected to the top of the distillation tower 5, the top receiving tank 7 is connected to the top heat exchanger 6, the inlet of the circulation pump 8 is connected to the top receiving tank 7, the outlet of the circulation pump 8 is connected to the top of the distillation tower 5, and the inlet of the distillation tower 5 is connected to the complexing device;

[0059] The reboiler 9 is connected to the bottom of the distillation tower 5 , the bottom heat exchanger 10 is connected to the reboiler 9 , and the bottom receiving tank 11 is connected to the bottom heat exchanger 10 .

[0060] Specifically, the inlet of the distillation tower 5 is connected to the outlet of the static mixer 4.

[0061] The inlet of the distillation tower 5 is connected to the outlet of the static mixer 4. The distillation product at the top of the distillation tower 5 passes through the top heat exchanger 6 and enters the top receiving tank 7. The distillation product at the bottom of the tower passes through the bottom heat exchanger 10 and enters the bottom receiving tank 11. The circulating pump 8 is used to transport the product of the bottom receiving tank 7 to the distillation tower 5.

[0062] Preferably, the trichlorosilane purification system in the polysilicon production further comprises a product storage tank 12.

[0063] The product storage tank 12 is connected to the tower top receiving tank 7, and / or the product storage tank 12 is connected to the outlet of the adsorption device.

[0064] Specifically, in this embodiment, the inlet of the static mixer 4 is connected to the tower top outlet of the adsorption column 2, the inlet of the distillation tower 5 is connected to the outlet of the static mixer 4, and the product storage tank 12 is respectively connected to the adsorption column 2 and the tower top receiving tank 7. When the product storage tank 12 receives the material in the adsorption column 2, the composition of the material collected in the product storage tank 12 is detected; when the product storage tank 12 receives the material in the tower top receiving tank 7, the composition of the material collected in the product storage tank 12 is detected.

[0065] Specifically, the distillation tower 5 is filled with fractionation packing (structured packing).

[0066] The present invention also provides a method for purifying trichlorosilane in polysilicon production using the above system, comprising the following steps:

[0067] Passing trichlorosilane produced in polysilicon production into an adsorption device, and performing adsorption treatment through an adsorbent filled in the adsorption device to obtain a first liquid;

[0068] Passing a liquid complexing agent into a complexing reaction device to mix with the first liquid entering therein, and performing a complexing reaction to obtain a second liquid;

[0069] The second liquid entering the distillation device is subjected to distillation treatment to obtain purified trichlorosilane.

[0070] Specifically, this embodiment provides a method for purifying trichlorosilane in polysilicon production using the above system, comprising the following steps:

[0071] (1) Trichlorosilane enters the bottom of the adsorption column 2, leaves the top of the adsorption column 2 after being adsorbed by the adsorbent, and enters the static mixer 4;

[0072] (2) the complexing agent is metered by a booster pump 3 and then enters a static mixer 4, trichlorosilane and the complexing agent are mixed in the static mixer 4 to form a mixed solution, and the concentration of the complexing agent added is 5-30 times the concentration of impurities in trichlorosilane;

[0073] (3) the mixed solution obtained in step (2) enters into a distillation tower 5, and after distillation and purification, purified trichlorosilane (refined trichlorosilane) is obtained at the top of the distillation tower 5, and liquid trichlorosilane is extracted from the bottom of the distillation tower 5;

[0074] (4) The refined trichlorosilane obtained at the top of the distillation tower 5 in step (3) enters the top heat exchanger 6 to obtain trichlorosilane condensate, part of the trichlorosilane condensate is refluxed to the distillation tower 5 through the circulation pump 8 for further distillation, and the other part of the trichlorosilane condensate enters the product storage tank 12; the liquid trichlorosilane obtained at the bottom of the distillation tower 5 in step (3) enters the bottom heat exchanger 10 and the bottom receiving tank 11 in sequence.

[0075] Among them, the impurity content of trichlorosilane entering the purification system is: phosphorus 592 ppb, boron 213 ppb, carbon impurities 150 ppb, metal impurities 253 ppb (total content).

[0076] Preferably, the flow rate of the flow controller 1 is 10 to 150 kg / h.

[0077] Specifically, the flow rate of the flow controller 1 in this embodiment is controlled to be 100 kg / h.

[0078] Preferably, the pressure of the adsorption column 2 is 0.5-2 MPa, and the temperature is 50-70°C.

[0079] Specifically, the pressure of the adsorption column 2 in this embodiment is 1.1 MPa and the temperature is 70°C.

[0080] Preferably, the pressure of the booster pump 3 is 1 to 5 MPa.

[0081] Specifically, the pressure of the booster pump 3 in this embodiment is 2 MPa.

[0082] Preferably, the pressure of the static mixer 4 is 0.5-2 MPa, and the temperature is 50-70°C.

[0083] Specifically, the pressure of the static mixer 4 in this embodiment is 1.1 MPa and the temperature is 70°C.

[0084] Preferably, the pressure of the distillation tower 5 is 0.3-0.8 MPa, and the temperature is 50-160°C.

[0085] Specifically, the pressure of the distillation tower 5 in this embodiment is 0.2 MPa, the top temperature of the distillation tower 5 is 10° C., and the bottom temperature of the distillation tower 5 is 50° C.

[0086] Preferably, the liquid complexing agent is one or more of N,N,N',N'-tetramethylethylenediamine, 1,2-biphenylthioethane, bis(2-dimethylaminoethyl) ether, triphenylsulfur chloride, 3-methoxypropionitrile, diethylene glycol diethyl ether, triethylchlorosilane, tetrahydrothiophene-3-one, tetrahydrothiopyran-4-one, ethylene glycol bis(propionitrile) ether, triisopropylchlorosilane, and ethoxyethyl cyanoacetate.

[0087] Specifically, the liquid complexing agent in this embodiment is diethylene glycol diethyl ether.

[0088] Preferably, the adsorbent is one or more of silica gel, activated carbon, molecular sieve, supported molecular sieve, and modified mesoporous silica.

[0089] Preferably, the molecular sieve is any one or more of molecular sieve SBA-15, molecular sieve MCM-41, molecular sieve MCM-48, molecular sieve 5A, molecular sieve 13X, β-type molecular sieve, and Y-type molecular sieve.

[0090] Specifically, the adsorbent in this embodiment is a supported molecular sieve and modified mesoporous silica (mass ratio is 1:1).

[0091] Specifically, the method in this embodiment has the following results for the removal efficiency of trichlorosilane in polysilicon production: phosphorus impurities 80.4%, boron impurities 95.6%, carbon impurities 83.1%, and metal impurities 85.7%.

[0092] The trichlorosilane method in the production of polysilicon in this embodiment is a new impurity removal process, which simultaneously removes trace amounts of boron impurities, phosphorus impurities, carbon impurities and metal impurities in trichlorosilane.

[0093] The invention aims at the problem that trace boron, phosphorus, carbon and metal impurities cannot be deeply and simultaneously removed due to the single impurity removal means in the trichlorosilane purification process. The trichlorosilane purification system and method in the polysilicon production of the invention adopt a purification process combining adsorption, complex reaction and distillation, remove impurities with low boiling points such as boron and phosphorus by adsorption, use a complexing agent to react with boron, phosphorus and metal impurities to generate a high boiling point complex, and further remove boron and phosphorus impurities and high boiling point metal impurities by distillation; the invention uses a loaded molecular sieve loaded with specific groups and modified mesoporous silicon as adsorbents, which have higher adsorption efficiency for phosphorus impurities; the complexing agent used in the invention has a complexing effect on boron, phosphorus and metal impurities and does not react with trichlorosilane; the trichlorosilane purification system and method provided by the invention can realize the simultaneous deep removal of impurity components in trichlorosilane gas, and the removal efficiency of phosphorus impurities is higher than 80.4%, the removal efficiency of boron impurities is higher than 95.6%, the removal efficiency of carbon impurities is higher than 83.1%, and the removal efficiency of metal impurities is higher than 85.7%.

[0094] Example 3

[0095] This embodiment also provides a method for purifying trichlorosilane in polysilicon production using the above system, which differs from the method in Embodiment 2 in that:

[0096] The flow rate of the flow controller is 10kg / h.

[0097] The pressure of the adsorption column was 0.5 MPa and the temperature was 50 °C.

[0098] The pressure of the booster pump is 1MPa.

[0099] The pressure of the static mixer was 0.5 MPa and the temperature was 50°C.

[0100] The pressure of the distillation tower is 0.8MPa, the top temperature of the distillation tower is 120℃, and the bottom temperature of the distillation tower is 160℃.

[0101] The liquid complexing agent is N,N,N',N'-tetramethylethylenediamine and 1,2-biphenylthioethane (mass ratio is 1:1).

[0102] The adsorbent is activated carbon.

[0103] The invention aims at the problem that trace boron, phosphorus, carbon and metal impurities cannot be deeply and simultaneously removed due to the single impurity removal means in the trichlorosilane purification process. The trichlorosilane purification system and method in the polysilicon production of the invention adopt a purification process combining adsorption, complex reaction and distillation, remove impurities with low boiling points such as boron and phosphorus by adsorption, use a complexing agent to react with boron, phosphorus and metal impurities to generate a high boiling point complex, and further remove boron and phosphorus impurities and high boiling point metal impurities by distillation; the invention uses a loaded molecular sieve loaded with specific groups and modified mesoporous silicon as adsorbents, which have higher adsorption efficiency for phosphorus impurities; the complexing agent used in the invention has a complexing effect on boron, phosphorus and metal impurities and does not react with trichlorosilane; the trichlorosilane purification system and method provided by the invention can realize the simultaneous deep removal of impurity components in trichlorosilane gas, and the removal efficiency of phosphorus impurities is higher than 62.8%, the removal efficiency of boron impurities is higher than 78.6%, the removal efficiency of carbon impurities is higher than 48.5%, and the removal efficiency of metal impurities is higher than 68.6%.

[0104] Example 4

[0105] This embodiment also provides a method for purifying trichlorosilane in polysilicon production using the above system, which differs from the method in Embodiment 2 in that:

[0106] The flow rate of the flow controller is 150kg / h.

[0107] The pressure of the adsorption column was 2 MPa and the temperature was 60 °C.

[0108] The pressure of the booster pump is 5MPa.

[0109] The pressure of the static mixer was 2 MPa and the temperature was 60°C.

[0110] The pressure of the distillation tower is 0.3MPa, the top temperature of the distillation tower is 50℃, and the bottom temperature of the distillation tower is 100℃.

[0111] The liquid complexing agent is bis(2-dimethylaminoethyl) ether, triphenylsulfur chloride, and 3-methoxypropionitrile (mass ratio is 2:1:1).

[0112] The adsorbent is supported molecular sieve and modified mesoporous silica (mass ratio is 1:1).

[0113] The present invention aims at the problem that the trace boron, phosphorus, carbon and metal impurities cannot be deeply and simultaneously removed due to the single impurity removal means in the trichlorosilane purification process. The trichlorosilane purification system and method in the polysilicon production of the present invention adopts a purification process combining adsorption, complex reaction and distillation, removes impurities with low boiling points such as boron and phosphorus by adsorption, uses a complexing agent to react with boron, phosphorus and metal impurities to generate a high boiling point complex, and further removes boron and phosphorus impurities and high boiling point metal impurities by distillation; the complexing agent used in the present invention has a complexing effect on boron, phosphorus and metal impurities, and does not react with trichlorosilane; the system and method for purifying trichlorosilane provided by the present invention can achieve simultaneous and deep removal of impurity components in trichlorosilane gas. The system and method for purifying trichlorosilane provided by the present invention can achieve simultaneous and deep removal of impurity components in trichlorosilane gas, with a removal efficiency of phosphorus impurities higher than 76.4%, a removal efficiency of boron impurities higher than 90.3%, a removal efficiency of carbon impurities higher than 65.9%, and a removal efficiency of metal impurities higher than 76.5%.

[0114] Example 5

[0115] This embodiment also provides a method for purifying trichlorosilane in polysilicon production using the above system, which differs from the method in Embodiment 2 in that:

[0116] The flow rate of the flow controller is 120kg / h.

[0117] The pressure of the adsorption column was 1.5 MPa and the temperature was 55 °C.

[0118] The pressure of the booster pump is 3MPa.

[0119] The pressure of the static mixer was 1.5 MPa and the temperature was 55°C.

[0120] The pressure of the distillation tower is 0.5MPa, the top temperature of the distillation tower is 80℃, and the bottom temperature of the distillation tower is 120℃.

[0121] The liquid complexing agent is triethylchlorosilane, tetrahydrothiophene-3-one, tetrahydrothiopyran-4-one, and ethylene glycol bis(propionitrile) ether (mass ratio is 1:1:1:2).

[0122] The adsorbents were molecular sieves SBA-15 and MCM-41 (mass ratio was 1:1).

[0123] The present invention aims at the problem that the trace boron, phosphorus, carbon and metal impurities cannot be deeply and simultaneously removed due to the single impurity removal means in the trichlorosilane purification process. The trichlorosilane purification system and method in the polysilicon production of the present invention adopts a purification process combining adsorption, complex reaction and distillation, removes impurities with low boiling points such as boron and phosphorus by adsorption, uses a complexing agent to react with boron, phosphorus and metal impurities to generate a high boiling point complex, and further removes boron and phosphorus impurities and high boiling point metal impurities by distillation; the complexing agent used in the present invention has a complexing effect on boron, phosphorus and metal impurities, and does not react with trichlorosilane; the system and method for purifying trichlorosilane provided by the present invention can achieve simultaneous and deep removal of impurity components in trichlorosilane gas. The system and method for purifying trichlorosilane provided by the present invention can achieve simultaneous and deep removal of impurity components in trichlorosilane gas, with a removal efficiency of phosphorus impurities higher than 68.2%, a removal efficiency of boron impurities higher than 77.6%, a removal efficiency of carbon impurities higher than 42.3%, and a removal efficiency of metal impurities higher than 70.1%.

[0124] Example 6

[0125] This embodiment also provides a method for purifying trichlorosilane in polysilicon production using the above system, which differs from the method in Embodiment 2 in that:

[0126] The liquid complexing agent is triisopropylsilyl chloride and ethoxyethyl cyanoacetate (2:1).

[0127] The adsorbents were molecular sieve MCM-48, molecular sieve 5A, and molecular sieve 13X (mass ratio was 1:1:1).

[0128] The present invention aims at the problem that the trace boron, phosphorus, carbon and metal impurities cannot be deeply and simultaneously removed due to the single impurity removal means in the trichlorosilane purification process. The trichlorosilane purification system and method in the polysilicon production of the present invention adopts a purification process combining adsorption, complex reaction and distillation, removes low-boiling impurities such as boron and phosphorus by adsorption, uses a complexing agent to react with boron, phosphorus and metal impurities to generate a high-boiling complex, and further removes boron and phosphorus impurities and high-boiling metal impurities by distillation; the complexing agent used in the present invention has a complexing effect on boron, phosphorus and metal impurities, and does not react with trichlorosilane; the system and method for purifying trichlorosilane provided by the present invention can achieve simultaneous and deep removal of impurity components in trichlorosilane gas. The system and method for purifying trichlorosilane provided by the present invention can achieve simultaneous and deep removal of impurity components in trichlorosilane gas, with a removal efficiency of phosphorus impurities higher than 73.5%, a removal efficiency of boron impurities higher than 80.2%, a removal efficiency of carbon impurities higher than 46.3%, and a removal efficiency of metal impurities higher than 69.9%.

[0129] Example 7

[0130] This embodiment also provides a method for purifying trichlorosilane in polysilicon production using the above system, which differs from the method in Embodiment 2 in that:

[0131] The adsorbents are β-type molecular sieve, Y-type molecular sieve, and silica gel (mass ratio is 2:1:2).

[0132] The present invention aims at the problem that the trace boron, phosphorus, carbon and metal impurities cannot be deeply and simultaneously removed due to the single impurity removal means in the trichlorosilane purification process. The trichlorosilane purification system and method in the polysilicon production of the present invention adopts a purification process combining adsorption, complex reaction and distillation, removes impurities with low boiling points such as boron and phosphorus by adsorption, uses a complexing agent to react with boron, phosphorus and metal impurities to generate a high boiling point complex, and further removes boron and phosphorus impurities and high boiling point metal impurities by distillation; the complexing agent used in the present invention has a complexing effect on boron, phosphorus and metal impurities, and does not react with trichlorosilane; the system and method for purifying trichlorosilane provided by the present invention can achieve simultaneous and deep removal of impurity components in trichlorosilane gas. The system and method for purifying trichlorosilane provided by the present invention can achieve simultaneous and deep removal of impurity components in trichlorosilane gas, with a removal efficiency of phosphorus impurities higher than 77.5%, a removal efficiency of boron impurities higher than 87.1%, a removal efficiency of carbon impurities higher than 60.9%, and a removal efficiency of metal impurities higher than 72.4%.

[0133] Comparative Example 1

[0134] Only the adsorption device and product storage tank described in Example 2 are used. The adsorption device includes a flow controller 1 and an adsorption column 2, and the adsorption column is filled with an adsorbent. A first input pipeline, a flow controller 1, and an adsorption column 2 are connected to the adsorption column 2. The flow controller 1 is set on the first input pipeline. The first input pipeline is used to input trichlorosilane in polysilicon production. The adsorption column is connected to the product storage tank.

[0135] The process flow of purifying trichlorosilane in polysilicon production using the above system is as follows:

[0136] Trichlorosilane enters the adsorption column from the bottom, leaves the adsorption column from the top after being adsorbed by the adsorbent, and enters the product storage tank connected to the adsorption column.

[0137] Preferably, the adsorbent is one or both of modified molecular sieve and modified mesoporous silica;

[0138] The process parameters are controlled as follows:

[0139] The flow controller controls the flow rate to 100kg / h;

[0140] The pressure of the adsorption column was 1.1 MPa and the temperature was 70°C.

[0141] Removal efficiency results: phosphorus impurities 50.4%, boron impurities 76.9%, carbon impurities 46.3%, metal impurities 40.2%.

[0142] This comparative example is to investigate the impurity removal effect by adsorption operation alone.

[0143] Comparative Example 2

[0144] The trichlorosilane purification system described in Example 2 is used, including an adsorption device, a complex reaction device, a distillation device and a product storage tank, the adsorption device includes a flow controller 1 and an adsorption column 2, and the adsorption column is not filled with an adsorbent; the complex reaction device only uses a static mixer; the distillation device includes a distillation tower 5, a tower top heat exchanger 6, a tower top receiving tank 7, a circulating pump 8, a tower bottom heat exchanger 10 and a tower bottom receiving tank 11, the distillation tower is filled with a fractionation filler (structured filler), and the tower bottom is provided with a reboiler 9.

[0145] The process flow of purifying trichlorosilane using this system is as follows:

[0146] (1) Trichlorosilane enters the adsorption column from the bottom, the adsorption column is not filled with adsorbent, and leaves the adsorption column from the top to enter the static mixer;

[0147] (2) Without using a booster pump to add the complexing agent material, trichlorosilane directly passes through a static mixer and enters the distillation tower;

[0148] (3) Trichlorosilane enters a distillation tower, undergoes distillation and purification, and refined trichlorosilane is obtained at the top of the tower, while liquid trichlorosilane is extracted from the bottom of the tower;

[0149] (4) the refined trichlorosilane obtained at the top of the distillation tower in step (3) enters the top heat exchanger to obtain condensate and liquid-phase refined trichlorosilane, the condensate is refluxed to the distillation tower through the circulation pump to continue distillation, and the liquid-phase refined trichlorosilane enters the product storage tank; the liquid-phase trichlorosilane obtained at the bottom of the distillation tower in step (3) enters the bottom heat exchanger and the bottom receiving tank;

[0150] Preferably, the complexing agent is one or more of diethylene glycol diethyl ether, bis(2-dimethylaminoethyl) ether and ethylene glycol bis(propionitrile) ether.

[0151] The process parameters are controlled as follows:

[0152] The flow controller controls the flow rate to 100kg / h;

[0153] The pressure of the adsorption column and static mixer was 1.1 MPa and the temperature was 70 °C;

[0154] The pressure of the distillation tower is 0.2MPa, the top temperature is 10℃, and the bottom temperature is 50℃.

[0155] Removal efficiency results: phosphorus impurities 41.1%, boron impurities 53.8%, carbon impurities 43.4%, and metal impurities 68.9%.

[0156] Comparative Example 3

[0157] The trichlorosilane purification system described in Example 2 is used, including an adsorption device, a complex reaction device, a distillation device and a product storage tank, the adsorption device includes a flow controller 1 and an adsorption column 2, and the adsorption column is filled with an adsorbent; the complex reaction device only uses a static mixer; the distillation device includes a distillation tower 5, a tower top heat exchanger 6, a tower top receiving tank 7, a circulating pump 8, a tower bottom heat exchanger 10 and a tower bottom receiving tank 11, the distillation tower is filled with distillation filler (structured filler), and the tower bottom is provided with a reboiler 9.

[0158] The process flow of purifying trichlorosilane using this device is as follows:

[0159] (1) Trichlorosilane enters the adsorption column from the bottom, is adsorbed by the adsorbent, and leaves the adsorption column from the top to enter the static mixer;

[0160] (2) Without using a booster pump to add the complexing agent material, trichlorosilane directly passes through a static mixer and enters the distillation tower;

[0161] (3) Trichlorosilane enters a distillation tower, undergoes distillation and purification, and refined trichlorosilane is obtained at the top of the tower, while liquid trichlorosilane is extracted from the bottom of the tower;

[0162] (4) the refined trichlorosilane obtained at the top of the distillation tower in step (3) enters the top heat exchanger to obtain condensate and liquid-phase refined trichlorosilane, the condensate is refluxed to the distillation tower through the circulation pump to continue distillation, and the liquid-phase refined trichlorosilane enters the product storage tank; the liquid-phase trichlorosilane obtained at the bottom of the distillation tower in step (3) enters the bottom heat exchanger and the bottom receiving tank;

[0163] Preferably, the adsorbent is one or more of modified molecular sieve, silica gel and mesoporous silica;

[0164] Preferably, the complexing agent is one or more of diethylene glycol diethyl ether, bis(2-dimethylaminoethyl) ether and ethylene glycol bis(propionitrile) ether.

[0165] The process parameters are controlled as follows:

[0166] The flow controller controls the flow rate to 100kg / h;

[0167] The pressure of the adsorption column and static mixer was 1.1 MPa and the temperature was 70 °C;

[0168] The pressure of the distillation tower is 0.2MPa, the top temperature is 10℃, and the bottom temperature is 50℃.

[0169] Removal efficiency results: phosphorus impurities 63.5%, boron impurities 86.6%, carbon impurities 79.9%, metal impurities 70.2%.

[0170] Comparative Example 3 is to examine the impurity removal effect by adsorption and distillation without adding a complexing agent, and compare it with Example 2. The impurity removal effect without adding a complexing agent is compared with adsorption-complexation-distillation, which reflects the benefits of adsorption-complexation-distillation.

[0171] Comparative Example 1 is adsorption only, Comparative Example 2 is distillation only, and Comparative Example 3 is adsorption-distillation coupling, and the effect is better than that of Examples 2 and 3.

[0172] Only the adsorption device and product storage tank described in Example 2 are used. The adsorption device includes a flow controller 1 and an adsorption column 2, and the adsorption column is filled with an adsorbent.

[0173] The process flow of purifying trichlorosilane using this device is as follows:

[0174] Trichlorosilane enters the adsorption column from the bottom, leaves the adsorption column from the top after being adsorbed by the adsorbent, and enters the product storage tank connected to the adsorption column.

[0175] Preferably, the adsorbent is 13X molecular sieve;

[0176] The process parameters are controlled as follows:

[0177] The flow controller controls the flow rate to 100kg / h;

[0178] The pressure of the adsorption column was 1.1 MPa and the temperature was 70°C.

[0179] Removal efficiency results: phosphorus impurities 21.2%, boron impurities 53.2%, carbon impurities 42.6%, metal impurities 32.8%.

[0180] Comparing the results of Example 2 and Comparative Example 3, after adding the complex reaction device, the impurity removal efficiency can be further improved, with phosphorus impurities increased by 27%, boron impurities increased by 10%, carbon impurities increased by 4%, and metal impurities increased by 22%, which can significantly improve the adsorption rate of phosphorus impurities and metal impurities.

[0181] Comparing the results of Comparative Examples 1 and 4, under the operating conditions of using only the adsorption device, the adsorption effect of using the modified molecular sieve and mesoporous silica as adsorbents is greatly improved compared with the 13X molecular sieve, with phosphorus impurities increased by 94%, boron impurities increased by 45%, carbon impurities increased by 9%, and metal impurities increased by 23%. In particular, the loaded molecular sieve and modified silica can significantly improve the adsorption efficiency of phosphorus impurities.

[0182] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A trichlorosilane purification system in polysilicon production, characterized in that: include: An adsorption device filled with an adsorbent, the adsorption device is used to pass trichlorosilane in polysilicon production for adsorption treatment to obtain a first liquid; A complexing reaction device is connected to the adsorption device, and is used to introduce a liquid complexing agent to mix with the first liquid to perform a complexing reaction to obtain a second liquid; The distillation device is connected to the complexing device, and is used for distilling the second liquid to obtain purified trichlorosilane.

2. The trichlorosilane purification system in polysilicon production according to claim 1, characterized in that: The adsorption device comprises: a first input pipeline (13), a flow controller (1), an adsorption column (2), The first input pipeline (13) is connected to the adsorption column (2), the flow controller (1) is arranged on the first input pipeline (13), the first input pipeline (13) is used to input trichlorosilane in polysilicon production, and the adsorption column (2) is connected to a complex reaction device.

3. The trichlorosilane purification system in polysilicon production according to claim 1, characterized in that: The complex reaction device comprises: a second input pipeline (14), a booster pump (3), a static mixer (4), The second input pipeline (14) is connected to the static mixer (4), the booster pump (3) is arranged on the second input pipeline (14), the second input pipeline (14) is used for the liquid complexing agent, and the static mixer (4) is connected to the adsorption device.

4. The trichlorosilane purification system in polysilicon production according to claim 1, characterized in that: The distillation device comprises: a distillation tower (5), a tower top heat exchanger (6), a tower top receiving tank (7), a circulation pump (8), a reboiler (9), a tower bottom heat exchanger (10) and a tower bottom receiving tank (11). The tower top heat exchanger (6) is connected to the tower top of the distillation tower (5), the tower top receiving tank (7) is connected to the tower top heat exchanger (6), the inlet of the circulation pump (8) is connected to the tower top receiving tank (7), the outlet of the circulation pump (8) is connected to the tower top of the distillation tower (5), and the inlet of the distillation tower (5) is connected to the complexing device; the reboiler (9) is connected to the tower bottom of the distillation tower (5), the tower bottom heat exchanger (10) is connected to the reboiler (9), and the tower bottom receiving tank (11) is connected to the tower bottom heat exchanger (10).

5. The trichlorosilane purification system in polysilicon production according to claim 4, characterized in that: Also includes a product storage tank (12), The product storage tank (12) is connected to the tower top receiving tank (7), and / or the product storage tank (12) is connected to the outlet of the adsorption device.

6. A method for purifying trichlorosilane in polysilicon production using the system according to any one of claims 1 to 5, characterized in that: The following steps are involved: Passing trichlorosilane produced in polysilicon production into an adsorption device, and performing adsorption treatment through an adsorbent filled in the adsorption device to obtain a first liquid; Passing a liquid complexing agent into a complexing reaction device to mix with the first liquid entering therein, and performing a complexing reaction to obtain a second liquid; The second liquid entering the distillation device is subjected to distillation treatment to obtain purified trichlorosilane.

7. The method for purifying trichlorosilane in polysilicon production according to claim 6, characterized in that: When the device according to claim 2 is used, the flow rate of the flow controller (1) is 10 to 150 kg / h.

8. The method for purifying trichlorosilane in polysilicon production according to claim 6, characterized in that: When using the device of claim 2, the pressure of the adsorption column (2) is 0.5-2 MPa and the temperature is 50-70°C.

9. The method for purifying trichlorosilane in polysilicon production according to claim 6, characterized in that: When using the device of claim 3, the pressure of the booster pump (3) is 1 to 5 MPa.

10. The method for purifying trichlorosilane in polysilicon production according to claim 6, characterized in that: Using the device of claim 3, The pressure of the static mixer (4) is 0.5-2 MPa, and the temperature is 50-70°C.

11. The method for purifying trichlorosilane in polysilicon production according to claim 6, characterized in that: Using the device of claim 4, The pressure of the distillation tower (5) is 0.3-0.8 MPa, and the temperature is 50-160°C.

12. The method for purifying trichlorosilane in polysilicon production according to any one of claims 6 to 11, characterized in that: The liquid complexing agent is one or more of N,N,N',N'-tetramethylethylenediamine, 1,2-biphenylthioethane, bis(2-dimethylaminoethyl) ether, triphenylsulfur chloride, 3-methoxypropionitrile, diethylene glycol diethyl ether, triethylchlorosilane, tetrahydrothiophene-3-one, tetrahydrothiopyran-4-one, ethylene glycol bis(propionitrile) ether, triisopropylchlorosilane, and ethoxyethyl cyanoacetate.

13. The method for purifying trichlorosilane in polysilicon production according to any one of claims 6 to 11, characterized in that: The adsorbent is one or more of silica gel, activated carbon, molecular sieve, supported molecular sieve, and modified mesoporous silica.

14. The method for purifying trichlorosilane in polysilicon production according to claim 13, characterized in that: The molecular sieve is any one or more of molecular sieve SBA-15, molecular sieve MCM-41, molecular sieve MCM-48, molecular sieve 5A, molecular sieve 13X, β-type molecular sieve, and Y-type molecular sieve.

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