Solvent-Dry Stackable Tailings Production via Dual Solvent Extraction
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Solution Overview
Problem
Conventional methods for extracting bitumen from tar sands result in the production of tailings that are environmentally hazardous, difficult to dispose of, and lead to lower hydrocarbon yields due to the presence of precipitated asphaltenes and residual bitumen, as well as the generation of large volumes of sludge-like tailings that are costly and environmentally damaging.
Innovation Solution
A method involving multiple solvent extraction steps using hydrocarbon solvents to separate bitumen from tar sands, resulting in solvent-dry, stackable tailings that are easier to dispose of and more environmentally friendly, by dissolving bitumen in a first solvent, separating the bitumen-enriched phase, and then using a second solvent to displace and remove the first solvent, ultimately producing tailings with minimal residual solvent content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hot water extraction methods are used to separate bitumen from tar sands, then bitumen can be extracted, but the process produces large volumes of sludge-like tailings that are difficult to dispose of and environmentally hazardous
Solution Approach 1:
The patent changes the physical-chemical parameters of the extraction system by introducing hydrocarbon solvents (changing from water-based to organic solvent-based extraction). This parameter change transforms the tailings from water-rich sludge that requires retention structures to solvent-dry materials that can be stacked and disposed of conventionally, thereby resolving the environmental hazard issue while maintaining extraction efficiency
Solution Approach 2:
The patent extracts and removes the harmful component (solvent) from the tailings through a separate solvent recovery step. By taking out the hydrocarbon solvent from the tailings stream and recycling it, the process eliminates the environmental hazard associated with solvent-containing sludge while preserving the beneficial extraction function
2Productivity
If conventional extraction methods are used, then bitumen separation is achieved, but precipitated asphaltenes and residual bitumen in tailings lead to lower hydrocarbon yields
Solution Approach 1:
The patent changes the solvent parameters (using specific hydrocarbon solvents with controlled boiling points and solvating power) to optimize bitumen dissolution while preventing unwanted asphaltene precipitation. This parameter optimization ensures maximum hydrocarbon recovery in the extract phase while leaving minimal residual bitumen and asphaltenes in the tailings, thereby resolving the substance loss issue
Solution Approach 2:
The patent replaces the mechanical/physical separation mechanism (hot water agitation and froth flotation) with a chemical dissolution mechanism using hydrocarbon solvents. This substitution allows for more complete bitumen recovery by dissolving it into the solvent phase, reducing the loss of bitumen and asphaltenes that occurs with conventional mechanical separation methods
3Ease of manufacture
If conventional hot water process is used, then bitumen can be separated, but the tailings require costly retention structures for disposal
Solution Approach 1:
The patent changes the moisture content parameter of the tailings from high (water-rich sludge) to low (solvent-dry materials) by using hydrocarbon solvents instead of water and implementing solvent recovery. This parameter change transforms the tailings into a stackable, free-draining material that does not require costly retention structures, thereby resolving the device complexity issue while maintaining separation capability
Solution Approach 2:
The patent extracts and removes the liquid component (hydrocarbon solvent) from the tailings through a dedicated solvent removal step. By taking out the solvent and recycling it, the process produces dry, stackable tailings that can be disposed of in conventional landfills without requiring complex retention structures, eliminating the costly infrastructure requirement
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 significantly reduces the volume and environmental impact of tailings, enhances hydrocarbon recovery, and allows for more efficient disposal of tailings by producing stackable, dry materials that do not require costly retention structures.
Implementation Method 1
Mixing a first material comprising bitumen with a first solvent to form a first mixture
Implementation Method 2
Adding a second solvent to the first solvent-wet tailings to form second solvent-wet tailings
Implementation Method 3
Separating a bitumen-enriched solvent phase from the first mixture
Implementation Method 4
Removing the second solvent from the second solvent-wet tailings to form solvent-dry, stackable tailings
Data Source
AI summary
Methods for preparing solvent-dry, stackable tailings. The methods 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. The first solvent-wet tailings are washed with a second solvent that removes the first solvent from the tailings. Second solvent remaining in the tailings is removed to thereby produce solvent-dry, stackable tailings.