Hydrofluoropropene Refrigerant Stabilization with Phthalates
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Solution Overview
Problem
Hydrofluoropropene-based refrigerants face stability issues in the presence of air (oxygen), leading to oxidative degradation, acid generation, and system corrosion, which complicates their use in stationary air conditioners and requires enhanced stabilization techniques.
Innovation Solution
A refrigerant composition comprising hydrofluoropropene and a stabilizer selected from alkylcatechols, alkoxyphenols, benzoquinones, phenothiazines, and phthalates, with the stabilizer added in specific amounts to maintain stability, and a method for evaluating acid generation through heat-treatment and acid content analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If hydrofluoropropene is used as a refrigerant to achieve low GWP, then environmental performance is improved, but stability in the presence of oxygen deteriorates leading to oxidative degradation
Solution Approach 1:
A stabilizer is introduced as an intermediary substance that mediates between the hydrofluoropropene refrigerant and oxygen. The stabilizer preferentially reacts with oxygen or inhibits the oxidation mechanism, protecting the refrigerant from oxidative degradation while allowing the system to operate in the presence of air
Solution Approach 2:
The stabilizer converts the harmful oxidative degradation process into a beneficial protective mechanism. By sacrificing itself to react with oxygen or inhibit oxidation, the stabilizer transforms the potential harm to the refrigerant into a protective effect, maintaining system stability
2Reliability
If stabilizer is added to prevent oxidative degradation, then reliability is improved, but device complexity increases due to additional components
Solution Approach 1:
The patent optimizes the concentration parameter of the stabilizer to achieve effective protection with minimal addition. By carefully controlling the stabilizer amount within specific ranges, the system achieves reliable oxidation prevention while minimizing the impact on refrigerant properties and system complexity
3Adaptability or versatility
If hydrofluoropropene is used in stationary air conditioners requiring on-site charging, then adaptability is improved, but risk of air entrapment and oxidative degradation increases
Solution Approach 1:
The stabilizer is pre-added to the hydrofluoropropene refrigerant before charging into the stationary air conditioner system. This preliminary action ensures that protective measures are already in place before the refrigerant encounters oxygen during installation and operation, preventing oxidative degradation from the outset
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 refrigerant composition achieves stability equivalent to HFC refrigerants, preventing system corrosion and maintaining refrigeration capacity, while being chlorine- and bromine-free with low global warming potential, suitable for both mobile and stationary systems.
Implementation Method 1
the evaluation results confirmed that progressive oxidative degradation occurred even in the temperature range to which refrigerant compositions may be exposed during actual use, thus forming acids such as CF3COOH and HF
Data Source
AI summary
The present invention provides a stabilized refrigerant composition containing a hydrofluoropropene with low global warming potential (GWP) that can remain stable even in the presence of air (oxygen) for a long period of time. More specifically, the present invention provides a refrigerant composition containing a hydrofluoropropene and a stabilizer. The stabilizer is at least one member selected from the group consisting of alkylcatechols, alkoxyphenols, benzoquinones, phenothiazines, and phthalates.