Trichlorosilane Purification via Hydrocarbon Thermal Decomposition
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Solution Overview
Problem
Current trichlorosilane purification methods face difficulties in separating hydrocarbons with boiling points close to trichlorosilane, leading to reduced yield and increased chlorosilane discharge, making it challenging to produce high-purity trichlorosilane efficiently.
Innovation Solution
A thermal decomposition reactor converts hydrocarbons into low-boiling materials, enhancing the boiling point difference with trichlorosilane, allowing for easier separation, and a distiller separates trichlorosilane from other components, while controlling pressure and temperature within specific ranges and managing hydrogen ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distillation is used to purify trichlorosilane, then separation of trichlorosilane from hydrocarbons is attempted, but separation is difficult when boiling points are close
Solution Approach 1:
The patent changes the physical parameter of boiling point by converting hydrocarbons into compounds with significantly different boiling points through chemical reactions (chlorination to form high-boiling chlorinated hydrocarbons, or thermal decomposition to form low-boiling substances). This parameter change enables effective separation by distillation that was not possible when boiling points were close.
Solution Approach 2:
The patent converts the harmful presence of hydrocarbons (which have boiling points close to trichlorosilane and interfere with purification) into beneficial situations by transforming them into substances with vastly different boiling points. The hydrocarbons are converted either to high-boiling chlorinated compounds or low-boiling decomposition products, both of which facilitate separation from trichlorosilane.
2Manufacturing precision
If existing purification methods are used, then some purification is achieved, but large amounts of chlorosilanes must be discharged, reducing yield
Solution Approach 1:
The patent converts the harmful interference of hydrocarbons into beneficial separation opportunities by transforming them into substances with vastly different boiling points. This enables effective purification without discharging large amounts of chlorosilanes, as the converted hydrocarbon compounds can be separated and returned to the process.
Solution Approach 2:
The patent implements a system where hydrocarbons are converted to separable compounds, separated from trichlorosilane, and then recovered/returned to the process. This eliminates the need to discharge large amounts of chlorosilanes while maintaining high purification levels, thereby improving yield.
3Ease of manufacture
If hydrocarbons are converted to high-boiling materials by photochlorination, then separation becomes easier, but reaction control becomes difficult
Solution Approach 1:
The patent replaces the photochemical reaction system (which requires complex light source control and has safety issues) with a thermal decomposition system using controlled heat input. This substitution maintains the ability to convert hydrocarbons into separable compounds while significantly improving reaction control and operational safety.
Solution Approach 2:
The patent changes the reaction method from photochlorination to thermal decomposition, altering the energy input parameter from light to heat. This enables better control of the conversion process while achieving the same goal of creating compounds with different boiling points for easy separation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach increases trichlorosilane production efficiency without discharging large amounts of chlorosilanes, maintaining high-purity trichlorosilane production and preventing yield reduction in polycrystalline silicon production.
Implementation Method 1
a thermal decomposition reactor for thermally decomposing the hydrocarbons in the chlorosilane fraction to convert the hydrocarbons into low-boiling materials
Implementation Method 2
a distiller for separating trichlorosilane contained in the chlorosilane fraction transferred from the thermal decomposition reactor from other components
Data Source
AI summary
There is provided trichlorosilane purification technology in which it is unnecessary to discharge large amounts of chlorosilanes oat of the system in the production of high-purity trichlorosilane from a chlorosilane fraction containing hydrocarbons and in which the reaction control can also be easily performed. In the present invention, the step of converting hydrocarbons contained in a chlorosilane fraction into low-boiling materials by thermal decomposition has been provided in the purification system in order to easily separate the hydrocarbons. Thereby, the conversion of hydrocarbons into low-boiling materials by thermal decomposition and the separation are performed in the trichlorosilane purification cycle, and it is unnecessary to discharge large amounts of chlorosilanes out of the system. As a result, the trichlorosilane production efficiency is increased, and the problem of yield reduction of polycrystalline silicon does not arise either.