Spent Bleaching Earth Oil Extraction With Inert Slurry Separation
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Solution Overview
Problem
Existing methods for recovering residual oil from spent bleaching earth (SBE) are inefficient, costly, and hazardous due to the use of flammable and explosive solvents, leading to safety issues and high operational costs, particularly during slurry preparation and filtration.
Innovation Solution
A continuous process involving the preparation of a transportation slurry with non-explosive glyceridic oil, followed by multiple extraction stages using non-polar solvents like naphtha, and centrifuge decanters to separate and evaporate solvents, minimizing fire and explosion risks while ensuring efficient oil recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If flammable and explosive solvents are used for oil extraction, then oil recovery efficiency is improved, but safety risks and operational costs increase
Solution Approach 1:
The patent uses nitrogen gas to create an inert atmosphere during slurry preparation and solvent extraction operations. Nitrogen is introduced into extraction vessels and storage tanks to displace oxygen, preventing fire and explosion while allowing efficient oil recovery using flammable solvents like hexane. This resolves the contradiction by maintaining safety through atmospheric control rather than avoiding the solvents themselves.
Solution Approach 2:
The patent introduces nitrogen gas as an intermediary substance that mediates between the flammable solvent system and the oxygen-containing environment. The nitrogen acts as a protective barrier, allowing the extraction process to proceed efficiently with flammable solvents while preventing harmful combustion reactions. This intermediary approach enables both high productivity and safety.
2Productivity
If continuous extraction process is implemented, then productivity is improved, but process complexity increases
Solution Approach 1:
The continuous extraction process is segmented into distinct operational units: slurry preparation system, multiple extraction vessels operating in sequence, centrifugal separation units, and solvent recovery systems. Each segment performs a specific function and can be independently controlled or maintained. This segmentation enables continuous operation while managing complexity through modular design, allowing the system to process material continuously without requiring the entire system to be redesigned as one complex unit.
3Reliability
If regulated areas are established for safety, then safety is improved, but operational flexibility and cost increase
Solution Approach 1:
The patent extends the inert nitrogen atmosphere throughout the entire extraction system, including vessels, transfer lines, and storage tanks. This comprehensive inerting approach allows operations to proceed in ordinary areas without requiring specially designated regulated zones. The nitrogen atmosphere provides continuous safety assurance while maintaining operational flexibility, as standard equipment and facilities can be used without modification for regulated area compliance.
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 achieves safe, continuous, and economical recovery of residual oil from SBE, reducing fire hazards, eliminating the need for regulated areas, and minimizing downtime, with de-oiled SBE being stable for storage and disposal.
Implementation Method 1
a first centrifuge decanter separating said first agitated extraction slurry into at least a liquid full miscella and a sludge
Implementation Method 2
evaporating the non-polar solvent of said full miscella of step c) to recover glyceridic oil
Implementation Method 3
mixing said transportation slurry with a non-polar solvent and/or a miscella containing a non-polar solvent in the first extraction vessel to produce a first extraction slurry, said first extraction slurry being agitated to extract at least a fraction of the oil contained in said SBE
Data Source
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AI summary
A process for the treatment of oily hazardous solid materials such as for example spent bleaching earths. The process allows a safe and economical recovery of typically about 85% to 95% of the residual oil contained in such oily hazardous solid materials and transforms those ones into inert materials safe to transport, store, dispose of, or even makes them valuable for some applications. The process includes the production of a transportation slurry and at least one extraction slurry. The at least one extraction slurry is separated in at least one centrifuge decanter.