Method and device for purifying silicon tetrachloride of optical fiber grade through total reflux distillation

A silicon tetrachloride, total reflux technology, applied in the direction of halogenated silicon compounds, halogenated silanes, etc., can solve the problems of high equipment cost and energy consumption, insufficient impurity removal ability, and few types of impurity removal, etc., to reduce production costs, Easy to separate and meet process requirements

Inactive Publication Date: 2016-04-20
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The process has fewer types of impurity removal, insufficient impurity removal capacity, high equipment cost and energy consumption

Method used

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  • Method and device for purifying silicon tetrachloride of optical fiber grade through total reflux distillation
  • Method and device for purifying silicon tetrachloride of optical fiber grade through total reflux distillation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030](a) The silicon tetrachloride waste liquid preheated to 40°C enters the tower from the upper part of the light removal rectification tower. The number of trays in the light removal rectification tower is 40, and the feeding position is the 15th from top to bottom. block, the flow rate of the raw material liquid is: 1150kg / h, and the components of the raw material liquid are: 90% silicon tetrachloride; 9% trichlorosilane and 1% phosphorus trichloride, etc. The overhead steam of the light removal rectification tower 3 is condensed by the condenser 4 and continuously accumulated in the reflux tank 6. Maintaining the total reflux operation makes the light components continuously concentrated in the tower top. When the liquid in the reflux tank exceeds the operating liquid level (According to the actual operation situation, 70%), the liquid in the reflux tank beyond the overflow plate flows into the extraction area and is extracted; the operating pressure at the top of the tow...

Embodiment 2

[0033] (a) The silicon tetrachloride waste liquid preheated to 43°C enters the tower from the upper part of the silicon tetrachloride rectification tower. On the 16th board, the flow rate of the raw material liquid is: 1500kg / h, and the components of the raw material liquid are: 91.57% silicon tetrachloride; 8.4% trichlorosilane and 0.03% phosphorus trichloride, etc. The overhead steam of the light removal rectification tower 3 is condensed by the condenser 4 and continuously accumulated in the reflux tank 6. Maintaining the total reflux operation makes the light components continuously concentrated in the reflux tank. When the liquid in the reflux tank exceeds the operating liquid level (According to the actual operation situation, 70%), the liquid beyond the overflow plate in the reflux tank flows into the production area and then is produced; the operating pressure at the top of the tower is 210kPa, and the operating pressure at the bottom of the tower is 212.8kPa; the opera...

Embodiment 3

[0036] (a) The silicon tetrachloride waste liquid preheated to 45°C enters the tower from the upper part of the silicon tetrachloride rectification tower. For the 20th plate, the flow rate of the raw material liquid is 2000kg / h, and the components of the raw material liquid are: 92% silicon tetrachloride; 7% trichlorosilane and 1% phosphorus trichloride, etc. The overhead steam of the light removal rectification tower 3 is condensed by the condenser 4 and continuously accumulated in the reflux tank 6. Maintaining the total reflux operation makes the light components continuously concentrated in the reflux tank. When the liquid in the reflux tank exceeds the operating liquid level (According to the actual operation situation, 70%), the liquid in the reflux tank beyond the overflow plate flows into the extraction area and is extracted; the operating pressure at the top of the tower is 250kPa, and the operating pressure at the bottom of the tower is 260kPa; the operating temperatu...

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Abstract

The invention discloses a method for purifying silicon tetrachloride of optical fiber grade through total reflux distillation. The method comprises the following steps: after being preheated, silicon tetrachloride waste liquid enters a middle feed opening of a low boiling fraction removal rectifying tower, top steam of the low boiling fraction removal rectifying tower constantly accumulates in a reflux tank after being condensed by a condenser after rectification begins, and the total reflux operation is maintained, so that light components are constantly concentrated at the top of the low boiling fraction removal rectifying tower; when liquid in the reflux tank exceeds the operation liquid level, liquid above an overflow plate in the reflux tank flows into an extraction area to be extracted; tower bottoms, formed by silicon tetrachloride and phosphorus trichloride, of the low boiling fraction removal rectifying tower are discharged from the bottom of the low boiling fraction removal rectifying tower and pumped into a middle feed opening of a silicon tetrachloride purifying tower by a silicon tetrachloride feed pump; overhead fraction of the silicon tetrachloride purifying tower partially refluxes after being condensed by an overhead condenser of the silicon tetrachloride purifying tower, and the other part of overhead fraction is extracted, so as to obtain the silicon tetrachloride product of optical fiber grade. According to the method and the device, after compression, the relative volatility of trichlorosilane and silicon tetrachloride is improved, so that separation becomes easier.

Description

technical field [0001] The invention relates to the technical field of recovery and treatment of polysilicon tail gas, in particular to a new method and device for purifying fiber-grade silicon tetrachloride through total reflux rectification. Background technique [0002] Polysilicon is the basic material for manufacturing semiconductor devices, integrated circuits, and solar cells. In recent years, with the continuous development of computer technology and people's growing calls for environmental protection, energy saving and emission reduction, and the use of clean energy, the polysilicon industry has flourished. With the rise and development of the polysilicon industry, the trichlorosilane industry, which is the main raw material for polysilicon production, is also growing. At present, more than 80% of the world's polysilicon is produced by the improved Siemens method, and the remaining less than 20% is mainly produced by the silane thermal decomposition method. More a...

Claims

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Application Information

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IPC IPC(8): C01B33/107
CPCC01B33/107
Inventor 冯惠生孙德章王强钟鑫罗彬彬
Owner TIANJIN UNIV
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