Chlorosilane Production Catalyst Co Mo W
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Solution Overview
Problem
The existing processes for producing chlorosilanes from ultrahigh purity silicon dust in fluidized bed reactors are inefficient, requiring additional milling steps, high temperatures, and the use of metallurgical silicon, leading to increased costs and energy demands, with poor chlorosilane yield and high vulnerability to reactor failures.
Innovation Solution
A process using a fluidized bed reactor with a catalyst comprising Co, Mo, W, and optionally Zn, Cr, and Ni, allowing direct conversion of ultrahigh purity silicon dust into chlorosilanes at lower temperatures, eliminating the need for additional milling and metallurgical silicon, and optimizing chlorosilane selectivity and conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional processes are used to produce chlorosilanes from ultrahigh purity silicon dust, then the reaction requires high temperatures and additional milling steps, but this leads to increased energy costs, reduced productivity, and poor chlorosilane yield
Solution Approach 1:
The patent changes the chemical parameters of the reaction system by introducing specific catalysts (Co, Mo, W, or their carbides) to enable the reaction to proceed at lower temperatures (300-400°C instead of conventional higher temperatures), thereby improving energy efficiency and productivity
Solution Approach 2:
The patent introduces catalysts as intermediary substances that facilitate the reaction between silicon dust and hydrogen chloride, enabling the process to proceed more efficiently at lower temperatures and improving overall yield without requiring additional milling steps
2Productivity
If additional milling steps are performed on ultrahigh purity silicon dust, then the reaction efficiency may improve, but this increases process complexity and costs
Solution Approach 1:
The catalyst acts as an intermediary that compensates for the lack of additional milling by providing an alternative pathway for the reaction to proceed efficiently, thereby maintaining productivity without increasing process complexity
3Productivity
If conventional hydrochlorination processes are used without specific catalysts, then the process is simpler in terms of catalyst selection, but this results in poor chlorosilane yield and low selectivity
Solution Approach 1:
The patent optimizes the catalyst composition parameters by selecting from Co, Mo, W, or their carbides, which fundamentally changes the reaction pathway and improves both yield and selectivity of chlorosilane production
Solution Approach 2:
The patent employs composite catalyst systems where the active metal (Co, Mo, or W) is combined with support materials or used in specific forms (metallic, carbide), creating composite structures that enhance both the quantity and selectivity of chlorosilane production
4Speed
If high temperatures are used in the fluidized bed reactor, then the reaction rate increases, but this increases energy consumption and vulnerability to reactor failures
Solution Approach 1:
The patent changes the temperature parameter from conventional high temperatures to a lower range (300-400°C) by introducing catalysts, which compensates for the reduced thermal energy by providing an alternative reaction pathway with lower activation energy, thereby maintaining reaction rate while improving reliability
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 process enables direct conversion of ultrahigh purity silicon dust into chlorosilanes with improved selectivity and reduced energy costs, avoiding costly purification and disposal, and reducing the need for additional metallurgical silicon, while maintaining reactor stability and efficiency comparable to using metallurgical silicon.
Implementation Method 1
a catalyst, wherein the catalyst comprises at least one element from the group comprising Co, Mo and W
Implementation Method 2
a process for producing chlorosilanes in a fluidized bed reactor by reaction of a hydrogen chloride-containing reaction gas with a particulate contact mass
Data Source
AI summary
Generally unusable or difficultly useable dusts of ultrahigh purity silicon can be used to produce chlorosilanes under reasonable reaction conditions by employing a catalyst containing one or more of Co, Mo, W. The process may be incorporated into an integral plant for the production of polycrystalline silicon.