Bitumen Extraction via Solvent Dilution and Asphaltene Precipitation
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Solution Overview
Problem
Current methods for extracting bitumen from oil sands are inefficient, particularly due to the need for large quantities of process water and issues with removing bitumen from aqueous phases, and there is a continuous desire for improved process efficiency.
Innovation Solution
A non-aqueous solvent-based extraction process involving contacting oil sand with a solvent to create a solvent-diluted slurry, followed by filtration and separation steps to achieve a bitumen product with low solids content, where the filtration is optimized by dissolving asphaltenes to enhance filtration efficiency and induce asphaltene precipitation for fine solid removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If aqueous extraction processes are used to recover bitumen from oil sand, then bitumen can be separated from the oil sand, but extremely large quantities of process water are required and issues arise with removing bitumen from the aqueous phase and removing water from the bitumen-depleted sand
Solution Approach 1:
The patent changes the fundamental parameter of the extraction medium from aqueous (water-based) to non-aqueous (organic solvent-based). This parameter change eliminates the need for large quantities of process water while maintaining effective bitumen extraction, as the organic solvent selectively dissolves bitumen from the oil sand without creating emulsion formation issues associated with aqueous systems
Solution Approach 2:
The patent employs a two-stage filtration system where the first filtration stage produces a filtrate that is then subjected to a second filtration stage. This copying of the filtration process with different S/B ratios allows for progressive removal of solids while maintaining bitumen in solution, achieving both high extraction efficiency and low solids content in the final product
2Manufacturing precision
If filtration is performed to remove solids from the solvent-diluted oil sand slurry, then solids content is reduced, but filtration efficiency is limited when asphaltenes are not dissolved
Solution Approach 1:
The patent performs preliminary dissolution of asphaltenes in the solvent before filtration occurs. By ensuring all asphaltenes are dissolved in the solvent-diluted slurry prior to the filtration step, the filtration process can proceed efficiently without clogging from undissolved asphaltene particles, thereby achieving both high solids removal and maintained filtration rates
Solution Approach 2:
The patent utilizes the phase transition of asphaltenes from dissolved state to precipitated state by adjusting the S/B weight ratio. In the first filtration stage, asphaltenes remain dissolved enabling efficient filtration. In the second stage, by increasing the S/B ratio, asphaltenes precipitate out, allowing for additional solids removal and achieving very low solids content in the final bitumen product
3Manufacturing precision
If the S/B weight ratio is increased to induce asphaltene precipitation for fine solid removal, then solids content in product is reduced, but bitumen recovery efficiency may be affected
Solution Approach 1:
The patent segments the bitumen recovery process into two distinct stages: first recovery at a lower S/B ratio where asphaltenes remain dissolved and bitumen is efficiently extracted, and second recovery at a higher S/B ratio where asphaltenes precipitate for fine solids removal. This segmentation allows each stage to be optimized for its specific function, achieving both high bitumen recovery and low solids content in the final product
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 achieves a more efficient bitumen extraction with significantly lower solids content in the product, allowing for almost complete removal of fine solids and improved filtration rates, resulting in a more efficient and effective bitumen recovery process.
Implementation Method 1
under conditions under which all (or substantially all) asphaltenes in the bitumen are dissolved
Implementation Method 2
By combining specific parts of the bitumen-rich and solvent-rich filtrate streams, asphaltene precipitation is induced enabling almost complete removal of the fine solids from the product through settling
Data Source
AI summary
The present invention provides a method for extracting bitumen from an oil sand stream, the method including the steps of: (a) providing an oil sand stream; (b) contacting the oil sand stream with a liquid comprising a solvent thereby obtaining a solvent-diluted oil sand slurry; (c) separating the solvent-diluted oil sand slurry, thereby obtaining a first solids-depleted stream and a first solids-enriched stream; (d) filtering the first solids-enriched stream obtained in step (c), thereby obtaining bitumen-depleted sand and at least a first filtrate; (e) increasing the S/B weight ratio of at least a part of the first filtrate by combining it with a stream having a higher S/B weight ratio thereby obtaining a combined stream; and (f) separating the combined stream, thereby obtaining a second solids-depleted stream and a second solids-enriched stream.