Silicon Core Rod Heating for Trichlorosilane Production

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Solution Overview

Problem

Existing apparatus for producing trichlorosilane using carbon heaters face high costs and short operating lifetimes due to the need for silicon carbide coatings, which deteriorate over time, and produce impurities that contaminate the trichlorosilane.

Innovation Solution

The apparatus employs silicon core rods heated by an electric mechanism within a vessel, eliminating the need for carbon heaters and silicon carbide coatings, allowing for simultaneous production of trichlorosilane and silicon, and uses a heat-insulating material with a silicon carbide coating to enhance thermal efficiency and prevent silicon deposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If carbon heaters with silicon carbide coating are used to produce trichlorosilane, then the heating function is achieved, but the cost increases and the operating lifetime decreases due to coating deterioration

Engineering Contradiction:

Improveheating capabilityVSAvoidheater operating lifetime

Core Design Contradiction:

TemperatureVSDuration of action of stationary object

Solution Approach 1:

The invention extracts and removes the carbon component from the heating system, replacing carbon heaters with silicon core rods heated by an external heating mechanism. This eliminates the need for silicon carbide coating and prevents coating deterioration, thereby extending the heater's operating lifetime while maintaining the heating function.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the expensive and short-lived coated carbon heater with a cheaper, maintenance-free silicon core rod system. The silicon core rods do not require protective coating and have significantly longer service life, reducing both cost and replacement frequency.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Temperature

If carbon heaters with silicon carbide coating are used to produce trichlorosilane, then the heating function is achieved, but the cost of constituent members increases

Engineering Contradiction:

Improveheating capabilityVSAvoidcost of constituent members

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The invention extracts and removes the expensive silicon carbide coating from the heating system, using uncoated silicon core rods instead. This eliminates the cost of coating materials and application processes while maintaining effective heating through the external heating mechanism.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces expensive coated carbon heaters with cheaper silicon core rods that do not require protective coating. The simplified construction reduces material costs, manufacturing complexity, and maintenance expenses.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Temperature

If carbon heaters are used to produce trichlorosilane, then heating is achieved, but impurities are generated that reduce product purity

Engineering Contradiction:

Improveheating capabilityVSAvoidimpurity generation

Core Design Contradiction:

TemperatureVSObject-generated harmful factors

Solution Approach 1:

The invention extracts and removes carbon from the heating system by replacing carbon heaters with silicon core rods. This eliminates the source of carbon-based impurities (methane, methylchlorosilane, silicon carbide) that would otherwise contaminate the trichlorosilane product, thereby improving product purity.

Inventive Principle:

Principle #2Taking out (Extraction)

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 costs and extends the apparatus' operating life, producing high-purity trichlorosilane while depositing silicon on the core rods, thereby reducing the load on distillation columns and overall processing costs.

Implementation Method 1

a heating mechanism that heats the silicon core rods

Methodology Applied

Scientific EffectResistive heating: Joule Heating

Implementation Method 2

due to the reductive reaction and the thermolysis reaction of the trichlorosilane, which is produced by the conversion reaction, silicon is also deposited on the silicon core rods

Methodology Applied

Scientific EffectReductive reaction: Reduction

Implementation Method 3

due to the reductive reaction and the thermolysis reaction of the trichlorosilane

Methodology Applied

Scientific EffectThermolysis reaction: Pyrolysis

Data Source

PatentUS8034300B2Apparatus for producing trichlorosilane

Publication Date: 2011.10.11 HIGH-PURITY SILICON CORP

AI summary

This apparatus for producing trichlorosilane includes: a vessel having a gas inlet that introduces a feed gas into the vessel and a gas outlet that discharges a reaction product gas to the outside; a plurality of silicon core rods provided inside the vessel; and a heating mechanism that heats the silicon core rods, wherein a feed gas containing silicon tetrachloride and hydrogen is reacted to produce a reaction product gas containing trichlorosilane and hydrogen chloride. The silicon core rods may be disposed so as to stand upright on the bottom of the vessel, and the heating mechanism may have electrode portions that hold the lower end portions of the silicon core rods on the bottom of the vessel and a power supply that applies an electric current to the silicon core rods through the electrode portions to heat the silicon core rods.