Hydro(chloro)fluoroolefin Drying with Sulphuric Acid
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Solution Overview
Problem
Current methods for producing hydro(chloro)fluoroolefins, such as 1,3,3,3-tetrafluoropropene (HFO-1234ze) and 2,3,3,3-tetrafluoropropene (HFO-1234yf), face challenges in purifying product streams due to degradation from scrubbing techniques, leading to reduced yields and hazardous waste streams, and require efficient methods to remove unwanted water and by-products.
Innovation Solution
A method involving a first drying stage where a fluid stream containing hydro(chloro)fluoroolefins is contacted with sulphuric acid to reduce water content, followed by optional additional drying steps, using sulphuric acid concentrations between 60wt% and 98wt% to minimize product degradation and hazardous by-product formation, and subsequent treatment with adsorbent materials to achieve high purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If scrubbing techniques are used to purify hydro(chloro)fluoroolefin product streams, then product purity is improved, but product degradation increases and yield decreases
Solution Approach 1:
The patent changes the concentration parameter of sulphuric acid from conventional high concentrations (98wt%) to reduced concentrations (60wt%-90wt%). This parameter change reduces the degradation of hydro(chloro)fluoroolefin products while maintaining effective water removal capability, thereby resolving the contradiction between product purity and product yield
Solution Approach 2:
The patent implements a dynamic two-stage drying process where the first stage uses sulphuric acid at 60wt%-90wt% concentration for initial water removal, and the second stage uses sulphuric acid at 90wt%-98wt% concentration for final drying. This dynamic approach optimizes the balance between effective purification and minimal product degradation at each stage
2Quantity of substance
If concentrated sulphuric acid (98wt%) is used for drying, then water removal efficiency is improved, but product degradation increases
Solution Approach 1:
The patent segments the drying process into two distinct stages: first drying stage using sulphuric acid at 60wt%-90wt% concentration, and second drying stage using sulphuric acid at 90wt%-98wt% concentration. This segmentation allows the less aggressive first stage to remove the bulk of water, reducing overall product exposure to highly concentrated acid while maintaining effective drying
Solution Approach 2:
The patent applies partial action by using reduced concentration sulphuric acid (60wt%-90wt%) in the first drying stage, which is sufficient for removing the majority of water content without causing excessive product degradation. The full concentration is reserved for the second stage where only trace water remains
3Quantity of substance
If multiple drying stages are implemented, then water removal efficiency is improved, but process complexity increases
Solution Approach 1:
The patent uses sulphuric acid as a universal drying agent in both drying stages, varying only the concentration and contact time parameters. This multi-functionality of the same chemical agent simplifies the process compared to using different chemicals or technologies for each stage, reducing overall process complexity while maintaining high water removal efficiency
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 process effectively reduces water content in hydro(chloro)fluoroolefin streams to below 10 ppm, minimizes product degradation, and achieves high yields with reduced hazardous waste, allowing for the production of hydro(chloro)fluoroolefins in a substantially pure state, while managing the concentration of potentially hazardous materials in spent acid streams.
Implementation Method 1
contacting a first fluid stream comprising one or more hydro(chloro)fluoroolefins and water with a source of sulphuric acid to produce a first treated fluid stream comprising the hydro(chloro)fluoroolefin(s) and a first spent sulphuric acid stream, wherein the first treated fluid stream comprises a lower concentration of water than the first fluid stream
Implementation Method 2
subsequent treatment with adsorbent materials to achieve high purity
Data Source
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AI summary
The present invention provides a method for purifying a fluid comprising a first drying stage which comprises contacting a first fluid stream comprising one or more hydro(chloro)fluoroolefins and water with a source of sulphuric acid to produce a first treated fluid stream comprising the hydro(chloro)fluoroolefin(s) and a first spent sulphuric acid stream, wherein the first treated fluid stream comprises a lower concentration of water than the first fluid stream.