Method for producing 2,3,3,3-tetrafluoropropene
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Solution Overview
Problem
Current processes for producing 2,3,3-tetrafluoropropene (HFO-1234yf) require high operating pressures for separation, making it complex and costly due to the need for excessive compressor size, especially when fluorination reactions are conducted at lower pressures.
Innovation Solution
A process involving a fluorination reaction of halopropane/halopropene with hydrogen fluoride, followed by cooling, partial condensation, separation into gaseous and liquid fractions, and subsequent compression and distillation at moderate pressures, allowing for efficient separation and recycling of unreacted hydrogen fluoride, thereby reducing the need for large compressors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If fluorination reaction is carried out at lower pressure, then reactor operating conditions are improved, but compressor size becomes excessive due to large excess of HF
Solution Approach 1:
The gas stream from the fluorination reaction is separated into a gaseous fraction and a liquid fraction. The gaseous fraction is compressed using a compressor, while the liquid fraction is compressed using a pump. This segmentation allows the system to operate at lower reactor pressures without requiring excessive compressor size, as the pump handles the bulk of the liquid HF efficiently.
Solution Approach 2:
A separation column is introduced as an intermediary device between the fluorination reactor and the compression stages. This column separates the reaction mixture into gaseous and liquid fractions, enabling differentiated compression approaches. The separation column acts as a mediator that transforms the single-phase high-pressure requirement into a two-phase low-pressure system with selective compression.
2Manufacturing precision
If high operating pressure is used for separation by distillation, then separation efficiency is improved, but reactor must operate at even higher pressure which complicates the process
Solution Approach 1:
The compression and distillation process is segmented into two independent paths: one for the gaseous fraction and one for the liquid fraction. Each fraction is compressed to the required distillation pressure independently, allowing the separation column to operate at high pressure for efficient separation while the reactor operates at lower pressure. This eliminates the need for the entire process to operate at high pressure.
Solution Approach 2:
The physical state of hydrogen fluoride is changed from gaseous to liquid through partial condensation. This parameter change allows the liquid fraction to be pumped rather than compressed, reducing the pressure requirements for the reactor while maintaining high separation efficiency in the distillation column.
3Manufacturing precision
If gas phase is compressed before distillation, then separation is achieved, but excessive compressor size is required due to large excess of HF
Solution Approach 1:
The process utilizes phase transition of hydrogen fluoride from gas to liquid through partial condensation. By converting the majority of HF to liquid phase before compression, the system reduces the volume and mass flow that requires compression. The liquid fraction is then pumped to distillation pressure, avoiding the need for excessive compressor size.
Solution Approach 2:
The compression function is segmented between a compressor for the gaseous fraction and a pump for the liquid fraction. This segmentation allows the pump to handle the bulk of the liquid HF efficiently, while the compressor only needs to handle the smaller gaseous fraction, significantly reducing the overall compression equipment size.
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
Enables the production of HFO-1234yf at moderate pressures, simplifying the process and reducing equipment complexity by using pumps for liquid fractions and compressors for gaseous fractions, optimizing separation column design and reducing thermal power requirements.
Implementation Method 1
cooling and partial condensation of the gaseous stream resulting from the reaction, into a partially condensed stream
Implementation Method 2
distilling the compressed gas fraction and the compressed liquid fraction to provide a 2,3,3,3-tetrafluoropropene stream, a hydrochloric acid stream, and an unreacted hydrogen fluoride stream
Data Source
Figure 1~2
AI summary
The invention concerns a method for producing 2,3,3,3-tetrafluoropropene comprising: a fluoridation reaction of a halopropane and/or halopropene into 2,3,3,3-tetrafluoropropene by means of hydrogen fluoride; the recovery of a gas stream resulting from the reaction; the cooling and partial condensation of the gas stream resulting from the reaction into a partially condensed stream; the separation of the partially condensed stream into a gas fraction and a liquid fraction; the compression of the gas fraction into a compressed gas fraction; the compression of the liquid fraction into a compressed liquid fraction; the distillation of the compressed gas fraction and compressed liquid fraction in order to provide a stream of 2,3,3,3-tetrafluoropropene, a stream of hydrochloric acid, and a stream of unreacted hydrogen fluoride. The invention also concerns an installation suitable for implementing said method.