Catalytic Off-Gas Purification for Polysilicon Deposition

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Solution Overview

Problem

The conventional purification methods for off-gas from polysilicon deposition processes are energy-inefficient and costly due to the high energy consumption in removing hydrogen chloride, leading to increased operational costs and potential corrosion and leakage issues.

Innovation Solution

A purification method and apparatus using a catalytic reactor with an ion exchange resin catalyst to convert hydrogen chloride into chlorosilane-based compounds, reducing energy consumption and eliminating the need for energy-intensive distillation and absorption processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional distillation and absorption processes are used to remove hydrogen chloride from off-gas, then hydrogen chloride concentration is reduced, but energy consumption increases significantly

Engineering Contradiction:

Improvehydrogen chloride concentrationVSAvoidenergy consumption

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The invention changes the chemical parameters of the off-gas by introducing a catalytic reaction that converts hydrogen chloride into valuable chlorosilane products. This chemical transformation approach replaces the conventional physical separation methods (distillation and absorption), achieving hydrogen chloride removal while simultaneously producing useful materials and reducing energy consumption by approximately 40%.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention converts the harmful hydrogen chloride component into beneficial chlorosilane products through catalytic reaction. Instead of merely removing hydrogen chloride as waste, the process transforms it into valuable chemicals that can be reused in the polysilicon production process, thereby eliminating the need for energy-intensive removal operations.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If conventional purification processes are used, then hydrogen chloride is removed, but operational costs increase due to high energy consumption

Engineering Contradiction:

Improvehydrogen chloride concentrationVSAvoidoperational cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The catalytic conversion process transforms hydrogen chloride from a harmful waste product into valuable chlorosilane chemicals. This conversion eliminates the need for expensive energy-intensive purification operations and creates sellable or reusable products, thereby significantly reducing operational costs while maintaining effective hydrogen chloride control.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The invention changes the chemical composition parameters of the off-gas stream by catalytically converting hydrogen chloride into chlorosilanes. This parameter change approach replaces the conventional energy-intensive physical separation processes, leading to both lower operational costs and reduced environmental impact.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If high concentrations of hydrogen chloride are present in off-gas, then the purification process becomes necessary, but corrosion and leakage risks increase

Engineering Contradiction:

Improvepurification effectivenessVSAvoidcorrosion and leakage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The invention addresses the corrosion and leakage risks by converting hydrogen chloride into stable chlorosilane products through catalytic reaction. This transformation reduces the corrosive nature of the off-gas stream while simultaneously producing valuable chemicals, thereby enhancing purification effectiveness and reducing equipment damage risks.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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

The method effectively reduces hydrogen chloride concentration, minimizing energy use by up to 40% and preventing corrosion, while ensuring high-purity hydrogen recycling.

Implementation Method 1

A purification method and apparatus using a catalytic reactor with an ion exchange resin catalyst to convert hydrogen chloride into chlorosilane-based compounds

Methodology Applied

Scientific EffectCatalysis: Catalysis

Data Source

PatentUS10016724B2Purification method and purification apparatus for off-gas

Publication Date: 2018.07.10 HANWHA CHEMICAL CORPORATION

AI summary

The present invention relates to a purification method and a purification apparatus for off-gas. More specifically, the present invention relates to a purification method and a purification apparatus for off-gas, capable of lowering the concentration of hydrogen chloride and separating high-purity hydrogen from the off-gas, which is discharged after performing a polysilicon deposition process by a chemical vapor deposition reaction.