Pyrolysis Process for HFC-1234yf and HFC-1234ze Production

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Solution Overview

Problem

There is a need for new manufacturing processes for the production of hydrofluorocarbon refrigerants HFC-1234yf and HFC-1234ze, which have zero ozone depletion and low global warming potential, as existing methods are not sufficient.

Innovation Solution

A pyrolysis process is used to convert 1,1,1,2,3-pentafluoropropane (HFC-245eb) into HFC-1234yf and HFC-1234ze, involving a reactor with specific materials and conditions, including a temperature range of 450°C to 900°C and the absence of catalysts, to produce predominantly these refrigerants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If catalytic vapor phase dehydrofluorination is used to produce HFC-1234yf and HFC-1234ze, then the refrigerants can be produced with zero ozone depletion potential, but the process requires separate production lines and catalysts for each isomer

Engineering Contradiction:
Improveproduction capabilityVSAvoidprocess complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the production of HFC-1234yf and HFC-1234ze into a single pyrolysis process using one reactor system, eliminating the need for separate production lines and different catalysts. The unified process uses thermal energy alone to convert HFC-245eb into both refrigerant isomers simultaneously.

Inventive Principle:
Principle #5Merging (Combining)

2Productivity

If pyrolysis process is used to convert HFC-245eb, then both HFC-1234yf and HFC-1234ze can be produced in a single process, but high temperature conditions are required

Engineering Contradiction:
Improveproduction efficiencyVSAvoidreaction temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent optimizes the pyrolysis temperature range (450°C to 900°C) and residence time parameters to achieve high conversion efficiency. By carefully controlling these thermal parameters, the process achieves greater than 50% single-pass conversion while managing the high temperature requirements through efficient heat transfer design.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If single-pass conversion is increased to greater than 50%, then production efficiency improves, but unconverted HFC-245eb requires recovery and recycling systems

Engineering Contradiction:
Improvesingle-pass conversionVSAvoidrecovery system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements a recovery and recycling system for unconverted HFC-245eb. The process separates and recovers unreacted feedstock for reuse, while also utilizing azeotrope separation to purify the final refrigerant products. This approach maximizes material utilization and reduces waste.

Inventive Principle:
Principle #34Discarding and recovering

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 process effectively produces predominantly HFC-1234yf and HFC-1234ze, with greater than 50% single-pass conversion, allowing for efficient recovery and recycling of unconverted HFC-245eb, and enables the production of pure refrigerants through azeotrope separation.

Implementation Method 1

A pyrolysis process is used to convert 1,1,1,2,3-pentafluoropropane (HFC-245eb) into HFC-1234yf and HFC-1234ze

Methodology Applied
Scientific EffectPyrolysis: Pyrolysis

Implementation Method 2

enables the production of pure refrigerants through azeotrope separation

Methodology Applied
Scientific EffectAzeotrope separation: Distillation

Data Source

PatentUS7833434B2Tetrafluoropropene production processes
Publication Date: 2010.11.16 THE CHEMOURS CO FC LLC

AI summary

A process is disclosed for producing 2,3,3,3-tetrafluoropropene and 1,3,3,3-tetrafluoropropene. The process involves pyrolyzing 1,1,1,2,3-pentafluoropropane.