Process for purifying (hydro) fluoropropenes contaminated with halogenated ethane
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Solution Overview
Problem
The separation of (hydro)fluoroolefins from undesired halogenated ethanes and methanes is difficult due to the formation of minimum boiling azeotropes, such as R-134a and R-1234yf, making distillation challenging and costly, which is unattractive for the refrigerant supply chain.
Innovation Solution
A process using an adsorbent with pores having openings of about 6 Å or less, preferably zeolite molecular sieves, to selectively retain undesired halogenated ethanes and methanes, reducing their concentration in a composition containing desired (hydro)fluoroolefins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distillation is used to separate (hydro)fluoroolefins from halogenated ethanes, then separation can be achieved, but the process becomes very expensive and complex due to azeotrope formation
Solution Approach 1:
The patent employs molecular sieve adsorbents with specific pore sizes (3Å, 4Å, 5Å, or 6Å) that selectively adsorb halogenated ethanes and methanes from refrigerant mixtures. The porous structure allows size-based separation where smaller halogenated molecules enter and are retained in the pores while larger (hydro)fluoroolefin molecules pass through, achieving separation without complex distillation equipment.
Solution Approach 2:
The invention changes the separation mechanism from thermal distillation to adsorption-based separation using molecular sieves. This parameter change eliminates the need for complex twin-column distillation systems while achieving effective separation of azeotropic mixtures, reducing both equipment complexity and operational costs.
2Manufacturing precision
If twin column distillation system is used to separate azeotropes, then separation can be achieved, but the system becomes very expensive to build and operate
Solution Approach 1:
Molecular sieve adsorbents with specific pore sizes provide a cost-effective alternative to expensive twin-column distillation systems. The adsorbents can be contained in simple vessels and regenerated in place, eliminating the need for complex distillation infrastructure while achieving the required separation purity for refrigerant recovery.
Solution Approach 2:
The molecular sieve adsorbents can be regenerated in situ by heating or pressure cycling, allowing the separation system to restore its capacity without requiring complex external regeneration equipment. This self-service capability reduces both capital and operational costs compared to twin-column distillation systems.
3Manufacturing precision
If complex distillation system is used for separation, then separation can be achieved, but operation becomes complex and unattractive for refrigerant supply chain
Solution Approach 1:
The molecular sieve-based system simplifies operation compared to complex distillation systems. The adsorbent materials automatically selectively capture halogenated contaminants as refrigerant flows through the system, requiring minimal operator intervention and no complex control systems, making it suitable for widespread use in the refrigerant supply chain.
Solution Approach 2:
The adsorption system operates automatically based on the inherent selective adsorption properties of the molecular sieves. Regeneration can be performed in situ by simple heating or pressure changes, eliminating the need for complex operational procedures associated with twin-column distillation systems.
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
Effectively reduces the concentration of undesired halogenated ethanes and methanes by 50% to 98% by retaining them in the adsorbent, making it feasible to recover and recycle low-GWP (hydro)fluoroolefins in refrigerant systems.
Implementation Method 1
contacting the composition with an adsorbent comprising pores having openings which have a size across their largest dimension of about 6 Å or less, for example so as to retain at least a portion of the ethanes and/or methanes in said adsorbent
Data Source
AI summary
A process for treating a composition comprising one or more desired (hydro)fluoroolefins and one or more undesired halogenated ethanes, halogenated methanes or mixtures thereof so as to reduce the concentration of at least one undesired halogenated ethane or halogenated methane, the process comprising contacting the composition with an adsorbent comprising pores having openings which have a size across their largest dimension of about 6 A or less.