High-Paraffinic Base Oil Dewaxing for Subzero Cloud Point

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Solution Overview

Problem

Existing methods struggle to effectively reduce the cloud point of base oils with high paraffinic content below 0°C, particularly for Group II and Group III oils, which are prone to waxy haze and affect lubrication performance.

Innovation Solution

A method involving a solvent mixture of a paraffinic naphtha fraction and a co-solvent, such as methyl ethyl ketone, is used to treat base oils, followed by cooling and mechanical separation to remove wax crystals, resulting in a de-waxed fraction with a cloud point below 0°C.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional solvent dewaxing methods are used on high paraffinic base oils, then the cloud point can be reduced, but the base oils with high paraffinic content (Group II and III) still form waxy haze and cannot achieve cloud point below 0°C

Engineering Contradiction:
Improvecloud pointVSAvoidlubrication performance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the solvent system by introducing a specific tertiary amine component (at least 5 wt%, preferably 10-50 wt%) in combination with conventional dewaxing solvents. This parameter change in solvent composition enables effective dewaxing of high paraffinic base oils to achieve cloud point below 0°C while maintaining lubrication performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite solvent system combining tertiary amine with conventional dewaxing solvents (such as aromatic hydrocarbons, naphthenes, or esters). This composite solvent mixture synergistically addresses the waxy haze problem in high paraffinic base oils that single solvents cannot resolve, achieving both low cloud point and clear appearance.

Inventive Principle:
Principle #40Composite materials

2Reliability

If high paraffinic content is maintained in Group II and III base oils, then lubrication performance is improved, but waxy haze forms adversely affecting the base oil

Engineering Contradiction:
Improvelubrication functionVSAvoidwaxy haze
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent selectively extracts waxy components from high paraffinic base oils using the tertiary amine-based solvent system. The solvent selectively dissolves and removes the harmful waxy haze-forming components while preserving the beneficial high paraffinic content (90% or more saturates) that provides good lubrication performance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The tertiary amine solvent acts as an intermediary that mediates between the high paraffinic base oil and the wax crystals. It facilitates the separation of wax from the base oil through selective solvation, allowing the base oil to maintain its high paraffinic content and lubrication properties while removing the waxy haze.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If conventional dewaxing solvents are used, then the process is simpler, but cloud point cannot be reduced below 0°C for high paraffinic base oils

Engineering Contradiction:
Improveprocess simplicityVSAvoidcloud point
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent modifies the solvent composition parameters by incorporating tertiary amine at specific concentrations (at least 5 wt%) into the dewaxing system. This parameter change enables the process to achieve cloud point below 0°C for high paraffinic base oils while maintaining the relative simplicity of solvent dewaxing operations.

Inventive Principle:
Principle #35Parameter changes

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 method effectively reduces the cloud point of high paraffinic base oils to below 0°C, ensuring they remain 'clear and bright', thereby maintaining lubrication performance.

Implementation Method 1

a solvent mixture, wherein the solvent mixture comprises a naphtha fraction and a co-solvent to obtain a solvent treatment mixture

Methodology Applied
Scientific EffectSolubility: Solvation

Implementation Method 2

subjecting the solvent treatment mixture to a solvent de-waxing step... to separate the de-waxed fraction from the wax

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Implementation Method 3

subjecting the solvent treatment mixture to a solvent de-waxing step... to separate the de-waxed fraction from the wax

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP3559157B1Haze-free base oils with high paraffinic content
Publication Date: 2026.01.14 SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV

AI summary

The present invention relates to a method for reducing the cloud point of a base oil with high saturates/ paraffinic content to below 0°C, wherein the method comprises subjecting said base oils to a cloud point reduction step comprising adding said base oil to a solvent mixture, wherein the solvent mixture comprises a paraffinic naphtha fraction and a co-solvent to obtain a solvent treatment mixture; and subjecting the solvent treatment mixture to a solvent de-waxing step.