Group III Base Stock Hydroprocessing for Oxidation Stability

Solution Overview

Problem

Existing lubricating oils face challenges in achieving high oxidation stability and low temperature performance without the need for additional additives, and there is a demand for improved quality in industrial oils regarding oxidation stability, cleanliness, and interfacial properties.

Innovation Solution

A process is developed to produce Group III base stocks from feed stocks with a solvent dewaxed oil viscosity index of 45 to 150, involving hydrotreating, hydrocracking, dewaxing, and hydrofinishing using a non-dealuminated, unidimensional 10-member ring pore zeolite catalyst, resulting in base stocks with a multi-ring naphthenes to single-ring naphthenes ratio less than 0.46 and improved oxidation stability and low temperature performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional base oils are used to meet engine oil specifications, then oxidation stability and low temperature performance can be achieved, but additional additives must be added which increases cost and may cause miscibility problems

Engineering Contradiction:

Improveoxidation stabilityVSAvoidadditive content

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by modifying the base oil composition through controlled hydroprocessing to achieve specific compositional parameters (naphthene ratios, viscosity index) that inherently provide improved oxidation stability and low temperature performance, eliminating the need for additional additives

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional base oils are used to meet engine oil specifications, then oxidation stability and low temperature performance can be achieved, but additional additives must be added which increases cost

Engineering Contradiction:

Improveoxidation stabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by modifying the base oil composition through controlled hydroprocessing to achieve specific compositional parameters (naphthene ratios, viscosity index) that inherently provide improved oxidation stability and low temperature performance, eliminating the need for additional additives

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If base oils are produced from higher boiling fractions via vacuum distillation, then base oil can be obtained, but the process requires extensive processing including solvent extraction and dewaxing

Engineering Contradiction:

Improvebase oil productionVSAvoidprocessing steps

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the complex processing into distinct functional stages: vacuum distillation to separate base oil from heavier fractions, hydroprocessing to modify molecular structure, and dewaxing to remove paraffinic components, with each stage optimized for specific purposes

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies parameter changes by controlling hydroprocessing conditions (temperature, pressure, catalyst type) to achieve specific compositional outcomes (naphthene content, viscosity index) that define the quality and performance characteristics of the final base oil

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 process produces base stocks with enhanced oxidation stability and low temperature performance, achieving viscosity indices up to 145 and kinematic viscosities greater than 2 cSt, while minimizing the use of additives.

Implementation Method 1

hydrotreating the feed stock under first effective hydrotreating conditions to produce a first hydrotreated effluent

Methodology Applied

Scientific EffectHydrogenation: Hydrogenation

Implementation Method 2

hydrocracking the bottoms fraction under effective hydrocracking conditions to produce a hydrocracked effluent

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 3

dewaxing the hydrocracked effluent under effective catalytic dewaxing conditions to produce a dewaxed effluent

Methodology Applied

Scientific EffectCrystallisation: Crystallisation

Implementation Method 4

fractionating the second hydrotreated effluent to produce at least a first diesel product fraction and a bottoms fraction

Methodology Applied

Scientific EffectDistillation: Distillation

Data Source

PatentEP3728529B1Preparation of group iii base stocks

Publication Date: 2025.07.02 EXXONMOBIL TECHNOLOGY & ENGINEERING CO

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AI summary

Disclosed are Group III base stocks comprising at least 30 wt % naphthenes, a viscosity index from 120 to 145; and a unique ratio of molecules with multi-ring naphthenes to single ring naphthenes (2R+N/1RN). A method for preparing the base stocks is also disclosed. Also disclosed is a lubricating oil having the base stock as a major component, and an additive as a minor component.