Bitumen Extraction Using Two-Solvent Phase Separation
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Solution Overview
Problem
Conventional bitumen extraction methods from tar sands using hot water result in low yield, environmental hazards, and costly sludge-like tailings, with additional challenges in solvent recovery and efficiency due to the use of aliphatic hydrocarbons and liquefied petroleum gasoline (LPG).
Innovation Solution
A method involving a first solvent extraction followed by the addition of a polar solvent to displace and separate the first solvent from the tailings, allowing for phase separation and easier solvent recovery, reducing environmental impact and operational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hot water extraction is used to separate bitumen from tar sands, then the extraction process can be performed, but the tailings produced contain precipitated asphaltenes and residual bitumen resulting in low yield and environmental hazards
Solution Approach 1:
The patent changes the extraction parameter from hot water to a two-solvent system (aliphatic hydrocarbon followed by aromatic hydrocarbon). This parameter change prevents asphaltene precipitation and eliminates sludge formation, achieving both high bitumen yield and environmentally safe tailings disposal.
Solution Approach 2:
The patent uses a composite solvent system comprising two different hydrocarbon solvents (aliphatic and aromatic) in sequence. This composite approach allows complete bitumen dissolution and recovery while producing clean, non-hazardous tailings that can be landfilled without environmental risk.
2Productivity
If aliphatic hydrocarbon solvent is used for bitumen extraction, then bitumen can be dissolved and recovered, but solvent recovery becomes complex and energy-intensive
Solution Approach 1:
The patent introduces an intermediary aromatic hydrocarbon solvent that facilitates the recovery process. The aromatic solvent displaces the aliphatic solvent from the bitumen mixture, and because aromatic solvents have higher boiling points, the separation and recovery process becomes more energy-efficient and less complex.
Solution Approach 2:
The patent utilizes phase transition differences between the two solvents. The aliphatic solvent (lower boiling point) is first used for extraction, then the aromatic solvent (higher boiling point) is added to displace it. The phase transition temperatures differ sufficiently to allow easy separation and recovery, reducing energy consumption compared to recovering a single low-boiling solvent.
3Ease of manufacture
If a single solvent extraction method is used, then the process is simple, but complete solvent removal from tailings is difficult and environmental hazards remain
Solution Approach 1:
The patent segments the extraction process into two distinct stages using two different solvents. The first stage uses aliphatic hydrocarbon for initial extraction, and the second stage uses aromatic hydrocarbon to displace and remove the first solvent. This segmentation ensures complete solvent removal from tailings while maintaining process simplicity.
Solution Approach 2:
The aromatic hydrocarbon acts as an intermediary substance that facilitates the removal of the aliphatic solvent from the system. By adding the aromatic solvent, the aliphatic solvent is displaced and can be easily separated, ensuring tailings are free from harmful solvent residues while the process remains straightforward.
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
This method enhances bitumen yield, minimizes solvent content in tailings, and simplifies the recovery and reuse of solvents, resulting in more environmentally friendly and cost-effective bitumen extraction.
Implementation Method 1
adding an aromatic solvent to the mixture to displace the aliphatic solvent from the mixture
Implementation Method 2
a first hydrocarbon solvent capable of complete or near complete dissolution of bitumen is mixed with the material comprising bitumen
Implementation Method 3
The mixture may then be heated to a temperature above the boiling point temperature of the aromatic solvent
Implementation Method 4
The condensed aromatic solvent may then be separated from water and other immiscible liquids
Data Source
AI summary
Methods for extracting bitumen from bituminous material through the use of a polar solvent. The method may include a primary leaching or extraction process that separates most of the bitumen from a material comprising bitumen and produces first solvent-wet tailings. A polar solvent is added to the first solvent-wet tailings in order to remove the first solvent (plus any entrained bitumen) from the tailings. A mixture of polar solvent and first solvent produced by the addition of the polar solvent to the first solvent-wet tailings may be phase separated by maintaining the polar solvent-first solvent mixture for a period of time. Alternatively, the polar solvent and first solvent may leave the tailings in a phase separated state. Phase separation may occur due to the presence of water in the polar solvent-first solvent mixture. Water may also be added to the mixture of solvents to serve as an antisolvent and initiate phase separation. The separated solvents may then be recovered and reused in the method.