Stabilizing HCFO-1233zdE Isomerization with Volatile Alkenes
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Solution Overview
Problem
Trans-1-chloro-3,3,3-trifluoropropene (HCFO-1233zdE) undergoes isomerization to cis-1-chloro-3,3,3-trifluoropropene (HCFO-1233zdZ) at high temperatures, leading to performance loss in heat transfer applications, particularly in vapor compression systems with flooded evaporators, where existing stabilizers with high boiling points are ineffective due to concentration in the evaporator and failure to migrate to the condenser.
Innovation Solution
The use of C3 to C6 alkene compounds with a single double bond, such as butene or pentene, with boiling points less than 100°C and solidification temperatures below 0°C, specifically 2-methyl-but-2-ene or 3-methyl-but-1-ene, to stabilize HCFO-1233zdE and prevent isomerization, often in combination with other additives like lubricants and surfactants, to maintain the trans form and ensure effective heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If high boiling point stabilizers are used to prevent isomerization of HCFO-1233zdE, then thermal stability is improved, but the stabilizers concentrate in the evaporator and fail to migrate to the condenser, making them ineffective in flooded evaporator systems
Solution Approach 1:
The patent changes the key parameter of the stabilizer from high boiling point to low boiling point (below 100°C). This parameter change allows the stabilizer to remain in the fluid stream and migrate with the heat transfer fluid to the condenser, solving the effectiveness problem in flooded evaporator systems while maintaining thermal stability protection.
Solution Approach 2:
The patent uses volatile alkene compounds that can be replenished continuously. These short-living stabilizers evaporate and migrate with the heat transfer fluid, being replaced continuously rather than remaining permanently in the system like high boiling point stabilizers.
2Ease of operation
If C3 to C6 alkene compounds with low boiling points are used as stabilizers, then effectiveness in flooded evaporator systems is improved by remaining in the fluid stream, but the risk of polymerization increases
Solution Approach 1:
The patent uses the low boiling point alkene compound as an intermediary stabilizer that temporarily protects against isomerization during high temperature exposure, then migrates with the fluid stream to the condenser where it can be condensed and carried away, preventing polymerization accumulation.
Solution Approach 2:
The patent exploits phase transitions of the low boiling point stabilizer between vapor and liquid phases. The stabilizer evaporates with the heat transfer fluid, migrates through the system, and condenses in the condenser, using phase change to achieve distribution and prevent polymerization.
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 proposed solution effectively limits or prevents the isomerization of HCFO-1233zdE to HCFO-1233zdZ, maintaining the thermodynamic and thermophysical properties of HCFO-1233zdE, even at high temperatures, and ensures stable performance in vapor compression systems, especially those with flooded evaporators, by using alkene compounds that remain in the fluid stream and do not concentrate in the evaporator.
Implementation Method 1
The present invention relates to compounds making it possible to stabilize trans-1-chloro-3,3,3-trifluoropropene and more specifically to limit or prevent the isomerization of the trans form into the cis form
Implementation Method 2
using alkene compounds that remain in the fluid stream and do not concentrate in the evaporator
Implementation Method 3
HCFO-1233zdE is likely to be used in applications using flooded evaporators... in vapor compression systems such as air conditioning, refrigeration, heat pump systems
Data Source
AI summary
The invention relates to the use of a C3-C6 alkene compound comprising a single double bond, for limiting or preventing the isomerisation of trans-1-chloro-3,3,3-trifluoropropene into cis-1-chloro-3,3,3-trifluoropropene. The invention also relates to a composition comprising trans-1-chloro-3,3,3-trifluoropropene and a C3-C6 alkene compound comprising a single double bond, and to different uses of said composition.