Method and system for controlling balance of dichlorosilane in production of polycrystalline silicon

A dichlorosilane, balance control technology, applied in halosilanes, chemical instruments and methods, silicon compounds, etc., can solve problems such as unreasonable control of dichlorodihydrosilane, abnormal increase in polysilicon products, fluctuations in system parameters, etc. Guarantee the effect of processing and utilization, reduction of abnormal polysilicon products, and energy consumption

Active Publication Date: 2020-02-04
XINTE ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a method and system for the balance control of dichlorosilane in polysilicon production to solve the unreasonable control of dichlorodihydrosilicon in the polysilicon production process. , resulting in increased energy consumption, abnormal increase in polysilicon products, decreased yield, fluctuations in system parameters, poor utilization, etc.

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  • Method and system for controlling balance of dichlorosilane in production of polycrystalline silicon

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Experimental program
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Effect test

Embodiment 1

[0053] This embodiment also provides a system used in the balance control method of dichlorosilane in polysilicon production, including:

[0054] A chemical vapor deposition reactor, used for preparing polysilicon by chemical vapor deposition reaction;

[0055] The desorption tower is connected with the chemical vapor deposition reactor, and the tail gas for preparing polysilicon in the chemical vapor deposition reactor flows into the desorption tower, and the desorption tower is used for decomposing hydrogen chloride, and hydrogen chloride is obtained at the top of the desorption tower;

[0056] The first tail gas condensate separation tower is connected with the tower still of the analysis tower, the first tail gas condensate separation tower is used for rectification, and silicon tetrachloride is obtained in the tower still of the first tail gas condensate separation tower;

[0057] The second tail gas condensate separation tower is connected to the top of the first tail ga...

Embodiment 2

[0076] Such as figure 1 As shown, the present embodiment provides a system for the above-mentioned balance control method of dichlorosilane in polysilicon production, including:

[0077] Chemical vapor deposition reactor 1, used for preparing polysilicon by chemical vapor deposition reaction;

[0078] The analysis tower 2 is connected with the chemical vapor deposition reactor 1, and the tail gas for preparing polysilicon in the chemical vapor deposition reactor 1 flows in the analysis tower 2, and the analysis tower 2 is used for analyzing hydrogen chloride, and hydrogen chloride is obtained at the top of the analysis tower 2;

[0079] The first tail gas condensate separation tower 3 is connected with the tower still of the analysis tower 2, and the first tail gas condensate separation tower 3 is used for rectification, and silicon tetrachloride is obtained in the tower still of the first tail gas condensate separation tower 3;

[0080] The second tail gas condensate separat...

Embodiment 3

[0119] This embodiment provides a method for controlling the balance of dichlorosilane in polysilicon production using the system in Embodiment 2. The difference from the method in Embodiment 2 is:

[0120] The first preset molar percentage content of dichlorodihydrosilane is 8.3%; the second preset molar percentage content of dichlorodihydrosilane is 3.8%.

[0121] The temperature of the chemical vapor deposition reaction is 100°C and the pressure is 0.45MPa;

[0122] The temperature in the desorption tower is 122°C and the pressure is 0.9MPa;

[0123] The temperature in the first tail gas condensate separation tower is 135°C and the pressure is 0.78MPa;

[0124] The temperature of the second tail gas condensate separation tower is 84.5°C and the pressure is 0.45MPa.

[0125] The temperature of the cold hydrogenation reaction is 450°C and the pressure is 2.5MPa;

[0126] The temperature in the trichlorosilane separation tower is 62.5°C and the pressure is 0.23MPa;

[0127...

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Abstract

The invention discloses a method and system for controlling the balance of dichlorosilane in production of polycrystalline silicon. The method comprises the following steps: 1) analyzing tail gas of polycrystalline silicon prepared by a chemical vapor deposition reaction, then carrying out rectifying purification and separation, and carrying out rectifying purification and separation on synthesisgas which is used for synthesizing trichlorosilane by a cold hydrogenation reaction; 2) mixing a tower bottom liquid of a second tail gas condensation liquid separation tower and a tower bottom liquidof a last-stage trichlorosilane rectification tower to obtain a first mixture; 3) mixing a tower top liquid of the second tail gas condensation liquid separation tower and the first mixture to obtaina second mixture, and adjusting the flow rate to enable the mol percentage content of dichlorosilane in the second mixture to be a second preset mol percentage content of dichlorosilane; and 4) introducing the second mixture in to the chemical vapor deposition reaction in the step 1) as a raw material for continuously preparing polycrystalline silicon. According to the method, the content of dichlorosilane in the second mixture is accurately controlled, reasonable and effective treatment and utilization of dichlorosilane are ensured, and energy consumption is reduced.

Description

technical field [0001] The invention belongs to the technical field of polysilicon production, and in particular relates to a method and system for controlling the balance of dichlorosilane in polysilicon production. Background technique [0002] High-purity polysilicon production is usually prepared by the "modified Siemens (Siemens)" process, in which trichlorosilane (SiHCl 3 or TCS) gas is deposited onto the heated silicon core carrier in a hydrogen environment. In such a production process, only a small part of TCS is deposited as simple silicon, and the rest is discharged from the reactor in the form of gas, which usually contains more than 45% (mole fraction) is the TCS participating in the reaction, forming a part of 5-10% (mole fraction) dichlorosilane (SiH 2 Cl 2 or DCS), 45-50% (mol fraction) of silicon tetrachloride (SiCl 4 or STC), silicon powder (silicon or Si) and other by-products. [0003] The DCS produced in the production process has always been deeply ...

Claims

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Application Information

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IPC IPC(8): C01B33/035C01B33/107
CPCC01B33/035C01B33/1071C01B33/10757
Inventor 蒋鹏陈喜清陈国辉陈文岳王玉丽刘小凤
Owner XINTE ENERGY
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