Waste Lubricating Oil Pretreatment and Hydroprocessing for Group III+ Base Oil
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Solution Overview
Problem
Existing methods fail to efficiently produce high-performance Group III+ lubricating base oils from waste lubricating oil, which are in high demand due to environmental regulations and market preference for superior performance.
Innovation Solution
A method involving pretreatment, distillation, solvent extraction, and hydroprocessing using a catalyst to convert waste lubricating oil into a recycled lubricating base oil with a viscosity index greater than 130, including steps like coagulant addition, centrifugal separation, atmospheric and vacuum distillation, and use of unsupported catalysts like Ni, W, Mo, or Co oxides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional distillation and hydroprocessing methods are used on waste lubricating oil, then the production process is relatively simple, but the viscosity index of the resulting base oil cannot reach Group III+ standards (VI ≥ 130)
Solution Approach 1:
The hydroprocessing step is divided into two distinct stages: first hydroprocessing to remove impurities (sulfur, nitrogen), then a second hydroprocessing stage optimized for viscosity index improvement. This segmentation allows each stage to be optimized for its specific function, achieving Group III+ standards without requiring entirely new equipment
Solution Approach 2:
Before the main hydroprocessing steps, a pretreatment stage is implemented including coagulant addition and centrifugal separation to remove suspended particles and water. This preliminary action prevents catalyst poisoning and ensures optimal conditions for subsequent hydroprocessing, enabling higher viscosity index achievement
2Quantity of substance
If waste lubricating oil with high sulfur content (≥10,000 ppm) is directly hydroprocessed, then the feedstock utilization is maximized, but the catalyst performance deteriorates and production efficiency decreases
Solution Approach 1:
A pretreatment step is implemented before hydroprocessing that includes coagulant addition and centrifugal separation to remove suspended particles and water from the waste lubricating oil. This preliminary action prevents catalyst poisoning and ensures optimal conditions for subsequent hydroprocessing, maintaining both high feedstock utilization and production efficiency
Solution Approach 2:
The pretreatment process extracts and removes harmful impurities (suspended particles, water) from the waste lubricating oil feedstock before it enters the hydroprocessing unit. This extraction protects the catalyst and maintains production efficiency while still utilizing the maximum amount of valuable base oil
3Manufacturing precision
If multiple distillation stages are performed to recover specific boiling point fractions, then the base oil quality is improved, but the energy consumption and processing time increase significantly
Solution Approach 1:
Instead of performing exhaustive multi-stage distillation, the process performs atmospheric distillation to recover the main boiling point fraction, followed by a single vacuum distillation stage. This partial action approach achieves sufficient base oil quality for Group III+ classification while significantly reducing processing time and energy consumption compared to conventional multi-stage distillation
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 a recycled lubricating base oil with improved viscosity index, meeting Group III+ standards, reducing impurities, and enhancing performance while being environmentally friendly.
Implementation Method 1
step a) may include coagulant addition, centrifugal separation, or a combination thereof
Implementation Method 2
step a) may include coagulant addition, centrifugal separation, or a combination thereof
Implementation Method 3
b) a distillation step of performing distillation to recover a fraction having a specific boiling point from the first pretreated waste lubricating oil
Implementation Method 4
step c) may include solvent extraction
Implementation Method 5
d) a hydroprocessing step of hydroprocessing the second pretreated fraction recovered in step c) in the presence of a catalyst
Implementation Method 6
d) a hydroprocessing step of hydroprocessing the second pretreated fraction recovered in step c) in the presence of a catalyst
Data Source
Figure 1
AI summary
The present disclosure relates to a method for producing a recycled lubricating base oil from waste lubricating oil. The method includes: a) first pretreating the waste lubricating oil, b) performing distillation to recover a fraction having a specific boiling point from the first pretreated waste lubricating oil, c) second pretreating the fraction recovered in step b), and d) hydroprocessing the second pretreated fraction in the presence of a catalyst. The recycled lubricating base oil produced by the above method has a viscosity index (VI) of equal to or greater than 130. The proposed method makes it possible to produce a high-grade lubricating base oil using only waste lubricating oil as a feed, thereby reducing the cost of raw materials for production of lubricating base oil, and having the advantage of being environmentally friendly.