Used Oil Membrane Separation for Low-Temperature Re-Refining
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Solution Overview
Problem
Conventional re-refining processes for used oils face challenges such as equipment fouling, thermal efficiency loss, and high financial costs due to the need for high temperatures and caustic treatments, which are exacerbated by the variety and degradation of additives in used oils.
Innovation Solution
A membrane separation process using porous or semiporous membranes to separate contaminants and additives from used oils at lower temperatures, employing solvents below engine operating temperatures to produce a purified oil product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distillation is used to isolate base oil fraction, then separation of base oil from used oil is achieved, but equipment fouling and thermal efficiency loss occur due to high temperatures required
Solution Approach 1:
The invention changes the temperature parameter from conventional high-temperature distillation (>300°C) to low-temperature membrane separation (below engine operating temperatures, typically <150°C). This parameter change allows effective separation of base oil from used oil without causing thermal degradation and equipment fouling, while maintaining separation efficiency through selective membrane permeation based on molecular size and solubility differences
Solution Approach 2:
The invention replaces the thermal-mechanical distillation system with a membrane-based separation system. Instead of using heat and mechanical distillation equipment, the process uses membrane modules with selective pores that physically separate components based on size exclusion and solubility-diffusion mechanisms, eliminating the need for high-temperature heating equipment and reducing fouling
2Manufacturing precision
If caustic treatment is used to remove reactive additives, then additive removal is achieved, but additional compounds are introduced that are detrimental to lubricant formulations
Solution Approach 1:
The invention extracts and removes reactive additives from used oil through membrane separation based on their molecular characteristics. The membrane selectively retains additives while allowing base oil to pass through, achieving additive removal without introducing foreign compounds. The removed additives are separated as a concentrated stream that can be discarded or further processed, eliminating the need for caustic chemicals
3Object-affected harmful factors
If anti-foulant additives are incorporated into used oil, then equipment fouling is mitigated, but production costs increase and maintenance shutdowns are still required
Solution Approach 1:
Instead of adding anti-foulant additives to prevent fouling, the invention inverts the approach by using low-temperature membrane separation to prevent fouling from occurring in the first place. The separation process operates at temperatures below engine operating temperatures, preventing thermal degradation and deposit formation, thereby eliminating the need for anti-foulant additives and reducing maintenance shutdowns
4Manufacturing precision
If high temperatures are used for distillation, then base oil isolation is effective, but further reaction of additives occurs creating deposits
Solution Approach 1:
The invention changes the temperature parameter from high-temperature distillation (>300°C) to low-temperature membrane separation (below engine operating temperatures, typically <150°C). This parameter change prevents thermal degradation and further reaction of additives that would otherwise occur at high temperatures, eliminating deposit formation while maintaining effective base oil isolation through selective membrane permeation
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 effectively removes a wide range of contaminants, including high and low molecular weight additives and soot, minimizing equipment fouling and reducing maintenance interruptions, while maintaining thermal efficiency and eliminating the need for caustic treatments.
Implementation Method 1
introducing a used oil and a solvent to a separation unit under separation conditions selected to produce a purified oil product, the separation unit comprising a porous membrane, a semiporous membrane, or both; and separating the used oil to obtain an effluent comprising a purified oil product
Implementation Method 2
The membrane separation process can include using a separation medium, such as a porous membrane, to separate the various contaminants, such as water, soot, degraded molecules, etc., and additives from the lower molecular weight base oil fractions
Implementation Method 3
introducing a used oil and a solvent to a separation unit under separation conditions selected to produce a purified oil product
Data Source
AI summary
In an embodiment is provided a process to re-refine used oil that includes introducing a used oil and a solvent to a separation unit under separation conditions selected to produce a purified oil product, the separation unit comprising a porous membrane, a semiporous membrane, or both; and separating the used oil to obtain an effluent comprising a purified oil product. In another embodiment is provided an apparatus for re-refining used oil that includes a separation unit comprising a porous or semiporous membrane; a used oil feed coupled to an inlet of the separation unit; and an inlet of a diffusate collection unit coupled to an outlet of the separation unit. In another embodiment is provided a composition generated from a membrane separation process that includes a base oil, the composition having a soot content of about 0.05% or less.