Used Oil Co-Conversion with Esterification for Corrosion Control
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Solution Overview
Problem
Used lubricating oil (ULO) and used cooking oil (UCO) contain high levels of impurities such as metals, phosphorus, and acidic content, making them difficult to process directly in refineries, and conventional recycling methods are capital-intensive and inefficient.
Innovation Solution
A process involving the synergistic co-conversion of ULO and UCO in a reactor vessel at elevated temperatures to form fatty acid glycol esters, fractionating the mixture into lighter and heavier fractions, where the lighter fraction is processed in a steam cracker for petrochemicals and the heavier fraction in a delayed coker for value-added fuels, reducing impurities and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If used lubricating oil and used cooking oil are processed directly in refineries, then processing efficiency is improved, but hardware corrosion and catalyst deactivation occur due to high impurity content
Solution Approach 1:
The patent applies preliminary action by performing esterification treatment on used lubricating oil and used cooking oil before refinery processing. The oils are reacted with catalysts to form esters, which redistributes metal impurities to the high boiling fraction. This pre-treatment prevents hardware corrosion and catalyst deactivation in subsequent refinery operations while maintaining processing efficiency.
2Reliability
If conventional recycling methods are used for used oils, then impurity removal is achieved, but capital investment and processing cost increase significantly
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of impurities through esterification reactions. Metal impurities are redistributed to the high boiling fraction through chemical reaction mechanisms rather than requiring complex physical separation equipment. This reduces capital investment while achieving reliable impurity removal.
3Manufacturing precision
If used oils are treated with multiple processing steps to reduce impurities, then product quality is improved, but energy consumption increases
Solution Approach 1:
The patent merges the impurity removal function into the esterification reaction step itself. The chemical reaction simultaneously forms esters and redistributes metal impurities to the high boiling fraction in a single operation, eliminating the need for multiple separate treatment steps and reducing overall energy consumption while maintaining product quality.
4Quantity of substance
If used cooking oil is processed alone, then fatty acid content is high, but acidic content causes corrosion and catalyst deactivation
Solution Approach 1:
The patent converts the harmful acidic content into beneficial esters through the esterification reaction. The high fatty acid content in used cooking oil, which normally causes corrosion and catalyst deactivation, is transformed into ester compounds that are less harmful. The reaction conditions are optimized to maximize ester formation while redistributing metal impurities to the high boiling fraction.
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 reduces impurities, prevents hardware corrosion, and saves energy by integrating heat from the delayed coking unit, producing high-value petrochemicals and fuels while minimizing environmental impact.
Implementation Method 1
ULO is reacted in a reactor vessel at an elevated temperature with fatty acids rich in UCO to mitigate the acidic content, via. formation of fatty acid glycol esters
Implementation Method 2
The mixture is fractionated into lighter fraction which is utilized in steam cracker process while heavier fraction of the mixture is subjected to delayed coking process
Implementation Method 3
saves additional energy requirement in reboiler of prefractionation column by heat integrating reboiler of prefractionation column with hot Heavy Coker Gas Oil (HCGO) stream from Main Fractionator (MF) of DCU
Implementation Method 4
redistribute the metal impurities selectively to the high boiling fraction of the obtained ULO+UCO reaction mixture
Implementation Method 5
The lighter fraction (boiling range below 200°C) of ULO+UCO reaction mixture is fed to steam cracker unit for production of high value petrochemicals such as light olefins and aromatics
Implementation Method 6
The heavier fraction (boiling range above 200°C) is fed to delayed coker unit for production of value-added fuels
Data Source
Figure 1~2
Figure 3
AI summary
Used Lubricating Oil (ULO) and Used Cooking Oil (UCO) are waste oils generated from Automotive Machines/ Heavy Machinery, and Cooking/Frying respectively. These oils, unless recycled or refined using conventional methods, can no longer be used for their respective purposes. The conventional methods for recycling of these oils involve capex intensive technologies with multiple step processes. Moreover, these oils contain high levels of impurities in terms of Metals & Total Acid Number (TAN), which make them difficult to process directly in refineries. Hence, proper end use of these oils is still an area of concern which needs to be addressed. The present disclosure provides a process wherein synergistic co-conversion of ULO and UCO is done in a reactor vessel to reduce the impurity content of the ULO+UCO mixture and co-processing the heavier fraction of ULO+UCO mixture with residue feedstock in Delayed Coker Unit (DCU) to produce value added products while utilizing the lighter cut of ULO+UCO mixture in steam cracker to produce olefins and aromatics.