Chlorosilane Purification via Divided Column and Adsorber Recycle
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Solution Overview
Problem
Current processes for purifying chlorosilanes, such as trichlorosilane, require high energy and are economically disadvantageous due to the need for large amounts of adsorber media and additional apparatus complexity, while combining distillation columns with adsorbers is costly and inconvenient, especially in continuous operations for semiconductor-grade production.
Innovation Solution
A process involving two distillation columns with vertical dividing walls, where the bottoms stream from the second column is passed through an adsorber to remove boron-, phosphorus-, or arsenic-containing impurities and returned as reflux to the first column, allowing for material coupling and energy savings by doubling the theoretical plates without the need for vertical dividing walls, enabling easy integration and replacement of adsorbers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional distillation columns are used for purifying chlorosilanes, then separation of components is achieved, but energy consumption is high and production cost is elevated
Solution Approach 1:
The distillation column is divided into multiple sections (rectifying section, stripping section, and intermediate section) with different functional characteristics. Each section is optimized for specific separation tasks, allowing efficient removal of various impurities at different stages while reducing overall energy consumption compared to conventional single-stage distillation.
Solution Approach 2:
An adsorber is introduced as an intermediary component between the distillation column and the condenser. This adsorber removes trace impurities (boron, phosphorus, arsenic) from the vapor phase, enabling the distillation process to achieve high purity levels without requiring excessive energy input for multiple distillation stages.
2Manufacturing precision
If adsorbers are integrated with distillation columns for impurity removal, then purification effectiveness is improved, but apparatus complexity and capital cost increase
Solution Approach 1:
The adsorber is merged with the distillation column by positioning it within the column structure, specifically between the stripping section and the condenser. This integration combines the separation functions of distillation and adsorption in a single apparatus, achieving high purification effectiveness while minimizing the increase in apparatus complexity and capital cost.
3Manufacturing precision
If large amounts of adsorber media are used for impurity removal, then purification effectiveness is improved, but process cost and operational complexity increase
Solution Approach 1:
Instead of using large amounts of adsorber media throughout the entire system, the invention concentrates the adsorber in a specific location within the distillation column where it is most effective - in the vapor phase between the stripping section and condenser. This localized application achieves high purification effectiveness with minimal adsorber media, reducing both process cost and operational complexity.
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 configuration reduces energy requirements by approximately 50% and lowers capital costs, allowing for continuous operation without downtime for adsorber replacement, effectively achieving high-purity chlorosilane production with reduced impurities.
Implementation Method 1
an adsorber to remove boron-, phosphorus- or arsenic-containing impurities
Implementation Method 2
purification of chlorosilanes by distillation and adsorption
Data Source
AI summary
Separation of chlorosilane mixtures containing boron, arsenic, and/or phosphorus impurities is facilitated by a distillative separation using at least one divided column, with recycle streams to a first column being passed through an external absorbent for the impurities.