Used Lubricating Oil Hydroprocessing for Blend-Compatible Base Stocks
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Solution Overview
Problem
Existing methods for recycling used lubricating oil into high-quality Group II and Group III base stocks are inefficient, leading to blending degrades when combined with conventionally produced stocks, and do not meet the viscosity and stability requirements for integration into existing blending schemes.
Innovation Solution
A method involving tailored hydroprocessing steps and conditions, including demetallization, hydrotreatment, hydrofinishing, and optional dewaxing, to produce high-yield Group II and Group III base stocks from pre-processed used lubricating oil, utilizing catalysts like molybdenum and cobalt on alumina, and hydrofinishing with Pt or Pd on alumina or titania, to achieve desired viscosity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional recycling methods are used to produce base stocks from used lubricating oil, then the base stocks can be obtained, but the yield is low and blending degrades occur when combined with conventionally produced stocks
Solution Approach 1:
The patent applies parameter changes by optimizing hydroprocessing conditions including temperature (300-450°C), pressure (50-300 bar), and hydrogen-to-oil ratio (3:1 to 10:1) to transform used lubricating oil into base stocks with properties matching conventional Group II and Group III stocks. This resolves the contradiction by adjusting processing parameters to achieve both high yield and blending compatibility.
Solution Approach 2:
The patent segments the hydroprocessing into distinct stages: demetallization, hydrotreatment, and hydrofinishing, each with specific catalysts and conditions. This segmentation allows optimization of each stage to maximize yield while ensuring the final product meets blending specifications, resolving the contradiction between productivity and reliability.
2Manufacturing precision
If multiple processing steps are applied to improve base stock quality, then viscosity and stability requirements are met, but the process complexity increases
Solution Approach 1:
The patent combines demetallization, hydrotreatment, and hydrofinishing into a single integrated hydroprocessing unit with multiple catalyst beds. This merging approach achieves the required manufacturing precision for viscosity and stability while reducing device complexity compared to separate processing units, directly resolving the technical contradiction.
Solution Approach 2:
The hydroprocessing unit performs multiple functions simultaneously: demetallization removes metal contaminants, hydrotreatment saturates aromatics and removes sulfur/nitrogen, and hydrofinishing adjusts viscosity. This multi-functionality achieves precise manufacturing properties without requiring separate dedicated equipment for each function, resolving the contradiction between precision and complexity.
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 produces base stocks with viscosity index, cold crank simulator, and other properties within the range of conventionally produced Group II and Group III stocks, allowing seamless integration into existing blending schemes without blending degrades.
Implementation Method 1
contacting the pre-processed used lubricating oil with a demetallization catalyst in the demetallization section
Implementation Method 2
contacting an effluent from the demetallization section with a hydrotreatment catalyst in the hydrotreatment section and hydrotreating the effluent
Implementation Method 3
contacting the hydrotreated oil with a hydrofinishing catalyst in the hydrofinishing section to hydrofinish at least a portion of the hydrotreated oil
Data Source
AI summary
Methods relate to processing a used lubricating oil, to form high quality Group II base stocks and Group III base stocks from pre-processed used lubricating oil.