THPS Formulation Freezing Prevention via Glycol Eutectics

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Solution Overview

Problem

Existing formulations of tetrakis(hydroxymethyl)phosphonium sulfate (THPS) are not stable at low temperatures, particularly in applications such as oil and gas extraction, where they often freeze or phase-separate, leading to instability and inefficiency.

Innovation Solution

A composition comprising THPS, water, and either 1,2-propanediol, ethylene glycol, or glycerine, within specific weight percentage ranges defined by ternary phase diagrams, which maintains a free-flowing liquid state even at -40 °C, preventing freezing and phase separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If THPS formulations are stored at low temperatures, then biocidal effectiveness is maintained, but the compositions freeze or phase-separate

Engineering Contradiction:
Improvebiocidal effectivenessVSAvoidphysical stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent introduces polyethylene glycol as an intermediary substance that mediates between THPS and water at low temperatures. The PEG forms a eutectic mixture with THPS that remains liquid at temperatures below -40°C, preventing freezing and phase separation while maintaining biocidal effectiveness.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical-chemical parameters of the formulation by adding polyethylene glycol with specific molecular weights (200-20,000). This alters the freezing point depression and phase behavior of the system, enabling the composition to remain stable and liquid at low temperatures while preserving THPS's biocidal properties.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional solvents are used with THPS, then the composition is easy to prepare, but it freezes or phase-separates at low temperatures

Engineering Contradiction:
Improveformulation simplicityVSAvoidlow-temperature stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent creates a composite formulation system combining THPS, water, and polyethylene glycol. This composite material leverages the properties of each component: THPS provides biocidal activity, water provides solubility, and PEG provides low-temperature fluidity. The synergistic interaction prevents freezing and phase separation while maintaining ease of preparation.

Inventive Principle:
Principle #40Composite materials

3Reliability

If THPS concentration is increased for better biocidal performance, then effectiveness improves, but freezing point increases

Engineering Contradiction:
Improvebiocidal performanceVSAvoidfreezing point
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent applies local quality by creating distinct micro-environments within the formulation. The polyethylene glycol locally associates with THPS molecules to form eutectic complexes, allowing high THPS concentration for biocidal effectiveness while the PEG-THPS complexes maintain low freezing points. This local interaction resolves the contradiction between concentration and freezing point.

Inventive Principle:
Principle #3Local quality

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 compositions remain physically stable and free-flowing at -40 °C, addressing the instability issues of prior THPS solutions and ensuring consistent performance in low-temperature conditions.

Implementation Method 1

compositions which are stable at low temperatures are not known... compositions remain physically stable and free-flowing at -40 °C, addressing the instability issues of prior THPS solutions and ensuring consistent performance in low-temperature conditions

Methodology Applied
Scientific EffectFreezing point depression: Freezing

Implementation Method 2

maintains a free-flowing liquid state even at -40 °C, preventing freezing and phase separation

Methodology Applied
Scientific EffectPhase stability: Phase Change

Data Source

PatentEP3270698B1Freeze stable tetrakis(hydroxymethyl)phosphonium sulfate formulations
Publication Date: 2020.04.22 ROHM & HAAS CO
  • EP3270698B1 patent drawingFigure 1
  • EP3270698B1 patent drawingFigure 2
  • EP3270698B1 patent drawingFigure 3

AI summary

A composition comprising: (a) tetrakis(hydroxymethyl)phosphonium sulfate (THPS); (b) water; and (c) 1,2-propanediol; wherein the weight percentages of (a), (b) and (c) are within the area on a ternary phase diagram for (a), (b) and (c) bounded by five points: (A) 20% THPS/40% water/40% 1,2-propanediol; (B) 20% THPS/20% water/60% 1,2-propanediol; (C) 65% THPS/22% water/13% 1,2-propanediol; (D) 65% THPS/25% water/10% 1,2-propanediol; and (E) 40% THPS/28% water/32% 1,2-propanediol.