Thermal Decomposition of Fluorinated Materials for Anhydrous HF Production

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Solution Overview

Problem

Current methods for generating anhydrous hydrogen fluoride (HF) rely on intermediate calcium fluoride production and azeotropic distillation, which are costly and environmentally impactful, and do not efficiently process a wide variety of fluorinated materials, including polymers and gases.

Innovation Solution

Thermal decomposition of fluorinated materials at high temperatures followed by treatment with carbon at elevated temperatures to convert carbon dioxide to carbon monoxide, producing a gaseous product that can be condensed to high-purity anhydrous hydrogen fluoride, with optional microwave radiation for enhanced efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional methods using calcium fluoride production and azeotropic distillation are used, then anhydrous hydrogen fluoride can be produced, but the process is costly and environmentally impactful

Engineering Contradiction:
Improvepurity of anhydrous hydrogen fluorideVSAvoidcost and environmental impact of production process
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent extracts and eliminates the intermediate calcium fluoride production step and azeotropic distillation process from the conventional HF production pathway. By directly thermally decomposing fluorinated materials and treating with carbon, the method removes unnecessary intermediate steps, reducing both cost and environmental impact while maintaining high purity output.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces carbon as a mediator substance that converts carbon dioxide to carbon monoxide during the thermal decomposition process. This intermediary role of carbon enables the direct conversion of fluorinated materials to anhydrous HF without requiring calcium fluoride intermediates, simplifying the overall process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If conventional methods are used, then anhydrous hydrogen fluoride can be produced, but they do not efficiently process a wide variety of fluorinated materials including polymers and gases

Engineering Contradiction:
Improverange of fluorinated materials that can be processedVSAvoidefficiency of processing fluorinated materials
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent creates a universal processing method that can handle diverse fluorinated materials (polymers, gases, liquids) through a single thermal decomposition and carbon treatment approach. The method's universality is achieved by using general thermal decomposition conditions and carbon treatment that apply across different fluorinated material types, eliminating the need for material-specific processing protocols.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If thermal decomposition is performed at high temperatures, then direct conversion to anhydrous hydrogen fluoride is achieved, but energy consumption increases

Engineering Contradiction:
Improveyield of anhydrous hydrogen fluorideVSAvoidenergy consumption of thermal decomposition process
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent maintains continuous high-temperature thermal decomposition conditions to ensure complete conversion of fluorinated materials to anhydrous HF. By sustaining the high temperature process continuously, the method maximizes yield while the carbon treatment step continuously converts CO2 to CO, ensuring efficient energy utilization throughout the process.

Inventive Principle:
Principle #20Continuity of useful action

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 method provides a cost-effective, environmentally friendly, and efficient means to produce high-purity anhydrous hydrogen fluoride directly from fluorinated materials, including recycling fluorinated waste, without relying on calcium fluoride intermediates and azeotropic distillation, achieving high yields and low water content.

Implementation Method 1

thermally decomposing a fluorinated material into a gaseous effluent comprising hydrogen fluoride and carbon dioxide

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

Implementation Method 2

contacting the gaseous effluent with carbon at a temperature of at least 830 °C to convert the carbon dioxide to carbon monoxide

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 3

microwave radiation may be used to thermally decompose the fluorinated material, to treat the gaseous effluent with carbon, or both

Methodology Applied
Scientific EffectMicrowave radiation: Microwave Radiation

Implementation Method 4

The hydrogen fluoride from the gaseous product can then be condensed to form liquid anhydrous hydrogen fluoride

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP4263425B1Converting fluorinated materials into anhydrous hydrogen fluoride
Publication Date: 2024.02.28 3M INNOVATIVE PROPERTIES CO
  • EP4263425B1 patent drawingFigure 1
  • EP4263425B1 patent drawingFigure 2
  • EP4263425B1 patent drawingFigure 3~4

AI summary

Methods of converting a variety of fluorinated materials into anhydrous hydrogen fluoride are described. The methods include thermally decomposing the fluorinated materials into a gaseous effluent comprising hydrogen fluoride and carbon dioxide. This gaseous effluent is then treated with carbon at a temperature of at least 830 °C, converting the carbon dioxide to carbon monoxide (CO) and producing a gaseous product comprising the hydrogen fluoride, which can be condensed to generate anhydrous hydrogen fluoride. These methods can also be used to convert water contained in the gaseous effluent into hydrogen.