Carboxylate Heat Transfer Fluids for Low-Temperature Corrosion Protection

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Solution Overview

Problem

Existing aqueous heat transfer fluids face challenges with solubility and stability of higher carbon carboxylate corrosion inhibitors, limiting their effectiveness in providing corrosion protection and freezing point depression, especially at low temperatures.

Innovation Solution

A synergistic combination of C3 carboxylate freezing point depressants with C6-C16 carboxylate corrosion inhibitors, along with pH management using imidazole or similar compounds, enhances the solubility and stability of corrosion inhibitors, improving corrosion protection and freezing point depression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If higher carbon carboxylate corrosion inhibitors (C6-C16) are used to provide corrosion protection, then corrosion inhibition is improved, but solubility and stability deteriorate especially at low temperatures

Engineering Contradiction:
Improvecorrosion protectionVSAvoidsolubility and stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent introduces C3 carboxylate freezing point depressant as an intermediary substance that mediates between the C6-C16 corrosion inhibitors and the aqueous medium. This intermediary improves the solubility and stability of the higher carbon carboxylates at low temperatures through synergistic interactions, allowing the corrosion inhibitors to remain effective without precipitating or degrading.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical composition parameters by incorporating specific ratios of C3 carboxylate freezing point depressant combined with C6-C16 carboxylate corrosion inhibitors. This parameter change transforms the physical and chemical properties of the solution, enhancing solubility and stability while maintaining corrosion protection effectiveness across a wide temperature range.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If C3 carboxylate freezing point depressant is combined with C6-C16 carboxylate corrosion inhibitors, then solubility and stability are improved, but formulation complexity increases

Engineering Contradiction:
Improvesolubility and stabilityVSAvoidformulation complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The C3 carboxylate component serves multiple functions simultaneously: it acts as a freezing point depressant, a solubility enhancer for the C6-C16 corrosion inhibitors, and a stability promoter at low temperatures. This multi-functionality reduces the need for separate additives, simplifying the overall formulation despite the presence of multiple carboxylate types.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Temperature

If traditional glycol-based fluids are used, then freezing point depression is achieved, but environmental toxicity increases

Engineering Contradiction:
Improvefreezing point depressionVSAvoidenvironmental toxicity
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent replaces persistent, toxic glycol-based antifreeze compounds with biodegradable carboxylate salts (C3 and C6-C16) that naturally decompose more quickly in the environment. These carboxylate-based alternatives provide equivalent freezing protection without the long-term environmental persistence and toxicity associated with traditional glycols.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 combination provides improved corrosion protection and freezing point depression over a wider range of temperatures, maintaining stable solutions and efficient heat transfer properties, making the fluid more environmentally benign and effective compared to traditional glycol-based fluids.

Implementation Method 1

C3 carboxylate freezing point depressants with C6-C16 carboxylate corrosion inhibitors, along with pH management using imidazole or similar compounds, enhances the solubility and stability of corrosion inhibitors, improving corrosion protection and freezing point depression

Methodology Applied
Scientific EffectFreezing point depression: Freezing

Implementation Method 2

enhances the solubility and stability of corrosion inhibitors, improving corrosion protection and freezing point depression

Methodology Applied
Scientific EffectSolubility enhancement: Solvation

Implementation Method 3

Water is the most commonly used heat exchange fluid because of its universal availability, low cost, excellent heat transfer properties

Methodology Applied
Scientific EffectHeat convection: Convection

Implementation Method 4

exhibits an optimum combination of high specific heat, high thermal conductivity and low viscosity

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 5

inhibit corrosion of cooling system components

Methodology Applied
Scientific EffectCorrosion inhibition:

Data Source

PatentEP2789669B1Combinations of carboxylates for use as freezing point depressants and corrosion protection in heat-transfer fluids
Publication Date: 2023.12.20 ARTECO NV
  • EP2789669B1 patent drawingFigure 1
  • EP2789669B1 patent drawingFigure 2
  • EP2789669B1 patent drawing

AI summary

An aqueous heat transfer fluid comprising a C3 carboxylate freezing point depressant, either solely or in combination with C3-C5 carboxylate freezing point depressants, in combination with C6-C16 organic acid salt corrosion inhibitors, provides an antifreeze/coolant composition wherein the corrosion inhibitors exhibit uniquely enhanced solubility, especially at low temperatures, in synergistic combination with the selected carboxylate freezing point depressants.