Multi-Stage Counter-Current Froth Settler for Bitumen Recovery
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Solution Overview
Problem
Conventional methods for separating bitumen from froth in bitumen recovery processes are costly, energy-intensive, and require large equipment footprints, often resulting in inefficient bitumen recovery and increased risk of containment breaches due to the need for multiple separation vessels and solvents.
Innovation Solution
A single multi-stage counter-current vessel with internal structures is used, where bitumen froth is diluted with solvent and passed downward through the internals, while additional solvent flows counter-currently, creating a solvent gradient that aids in separating bitumen from water and solids, minimizing asphaltene rejection and enhancing recovery efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple gravity separation vessels are used for bitumen froth separation, then bitumen recovery is improved, but the equipment footprint and risk of containment breach increase
Solution Approach 1:
The patent combines multiple gravity separation stages into a single integrated vessel with multiple internal settling zones. The vessel contains a series of horizontal settling zones stacked vertically, allowing multi-stage separation to occur within one compact unit rather than requiring multiple separate vessels arranged horizontally.
Solution Approach 2:
The invention transitions from horizontal arrangement of multiple separation vessels to vertical stacking of settling zones within a single vessel. The internal structure creates multiple horizontal settling planes at different vertical levels, utilizing the vertical dimension to achieve multi-stage separation in a compact footprint.
2Productivity
If centrifuges are used for froth separation, then separation efficiency is improved, but energy consumption increases
Solution Approach 1:
The patent replaces the high-energy centrifugal separation mechanism with a passive gravity-based settling system. The vessel uses carefully designed internal structures that allow dense phases to settle and light phases to rise under gravity alone, eliminating the need for energy-intensive rotating mechanical separation systems.
Solution Approach 2:
The invention optimizes the density difference parameter between phases to enhance gravity separation effectiveness. By controlling froth composition and using appropriate solvents, the design maximizes the density contrast between bitumen, water, and solids, allowing efficient separation under gravity without requiring the high G-forces of centrifuges.
3Productivity
If multiple froth separation vessels are used, then bitumen recovery is enhanced, but the number of pumps and auxiliary equipment increases cost
Solution Approach 1:
The patent integrates multiple separation functions into a single vessel structure with internal settling zones. This consolidation eliminates the need for multiple separate pumps, feed systems, and control mechanisms that would be required for multiple independent vessels, reducing auxiliary equipment while maintaining multi-stage separation capability.
4Use of energy by moving object
If large volumes of solvent are used for each separation unit, then viscosity reduction is achieved, but cost and environmental risk increase
Solution Approach 1:
The patent optimizes solvent concentration and composition parameters to achieve effective viscosity reduction with minimal solvent volume. The internal settling zones are designed to maximize the effectiveness of the solvent by ensuring thorough mixing and contact, allowing lower solvent volumes to achieve the same rheological modification effect that would require larger volumes in less efficient systems.
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 approach reduces the need for multiple vessels, minimizes energy consumption, and enhances bitumen recovery by utilizing a solvent gradient within a single vessel, improving the separation efficiency and reducing the risk of asphaltene rejection and equipment stress.
Implementation Method 1
Bitumen and light components are carried with the solvent, by buoyancy, to the top of the vessel while solids and water fall to the bottom of the vessel
Implementation Method 2
solids and water fall to the bottom of the vessel
Implementation Method 3
additional of the solvent flows counter-current through the internals establishing a gradient of solvent concentration relative to hydrocarbon concentration therein
Implementation Method 4
when sufficient solvent is added, asphaltenes are rejected from the froth upon contact between the solvent and the heavy hydrocarbon fraction
Implementation Method 5
Large aggregates typically form between the water droplets, mineral solids and the rejected asphaltenes
Data Source
AI summary
A method of recovering bitumen from a froth utilizes solvent and a single settling vessel having a plurality of internals. The froth is diluted with enough solvent to reduce viscosity and is added to the vessel above the internals. Additional solvent is added below the internals, intermediate the internals or both and is flowed counter-current to the diluted froth flowing downwardly over the internals, forming a gradient of solvent concentration relative to hydrocarbon concentration throughout the internals, acting as multiple stages of separation. The bitumen and other light components, rise with the solvent to the top of the vessel. The heavier components, such as water, solids and asphaltene aggregates fall to the bottom by gravity. Where paraffinic solvents are used, the solvent-to-bitumen ratio (S:B) for the initial dilution of froth is below that at which asphaltenes are rejected. Substantially all asphaltene rejection occurs in the vessel as S:B increases therein.