HFO-1234yf Production with Partial Condensation and Split Compression
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Solution Overview
Problem
Current methods for producing 2,3,3-tetrafluoropropene (HFO-1234yf) require high operating pressures due to the low boiling points of HCl and HFO-1234yf, leading to complex and costly compressor designs, making it challenging to operate the fluorination reaction at moderate pressures.
Innovation Solution
A method involving reactive fluorination of halopropane/halopropene with hydrogen fluoride, followed by cooling, partial condensation, separation into gaseous and liquid fractions, compression, and distillation to produce HFO-1234yf, allowing for operation at lower pressures and simplifying the process by using a pump for the liquid fraction instead of a compressor for gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high operating pressure is used for distillation to condense gases at the top of columns, then the condensation temperature is not too low and is compatible with standard cold units, but the reactor must be operated at even higher pressure which complicates the process and increases equipment complexity
Solution Approach 1:
The gaseous stream from the reaction is divided into a gaseous fraction and a liquid fraction through partial condensation. The liquid fraction is compressed using a pump while the gaseous fraction is compressed using a compressor, allowing each compression device to be optimized for its specific phase and size requirements
Solution Approach 2:
The process operates the fluorination reaction at moderate pressure (lower than distillation pressure) and uses a two-stage compression system with intercooling. The first compressor compresses the gaseous fraction to an intermediate pressure, then after cooling and partial condensation, the second compressor compresses the remaining gas to the final high pressure required for distillation
2Device complexity
If the fluorination reaction is carried out at lower pressure, then compressor size and complexity are reduced, but the gases obtained from the reaction have to be compressed before distillation which implies an excessive compressor size due to the substantial excess of HF used
Solution Approach 1:
The gaseous stream is separated into gaseous and liquid fractions through partial condensation. Only the gaseous fraction (which is smaller in volume than the total stream) needs to be compressed by the compressor, while the liquid fraction is handled by a pump, significantly reducing the required compressor size
Solution Approach 2:
Partial condensation is performed before compression to remove a portion of the HF and other condensable components from the gaseous phase. This preliminary separation reduces the volume and mass of gas that needs to be compressed
3Productivity
If high pressure is used in the reactor to enable distillation without excessive compression, then the distillation can be performed efficiently, but it is desirable to operate at relatively low pressure in the reactor for certain process configurations
Solution Approach 1:
The process separates reactor operation from distillation operation in terms of pressure conditions. The reactor operates at moderate pressure while a two-stage compression system bridges the pressure gap, allowing each unit to operate at its optimal pressure
Solution Approach 2:
The system uses a dynamic two-stage compression approach where the compression ratio is distributed across two stages with intercooling, allowing the reactor to operate at lower pressure while still achieving the high pressure needed for efficient distillation
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 approach enables the production of HFO-1234yf at moderate pressures, reducing compressor size and complexity, and optimizing the design of separation columns, while minimizing the size and heating power required for the condenser and reboiler.
Implementation Method 1
reactively fluorinating a halopropane and/or halopropene to 2,3,3,3-tetrafluoropropene using hydrogen fluoride
Implementation Method 2
cooling and partially condensing the gaseous stream obtained from the reaction
Implementation Method 3
distilling the compressed gaseous fraction and the compressed liquid fraction to give a 2,3,3,3-tetrafluoropropene stream, a hydrochloric acid stream, and a stream of unreacted hydrogen fluoride
Data Source
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.