Liquid Bath Seal for Bitumen Extraction Rejects
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Solution Overview
Problem
Non-aqueous solvent extraction of bitumen from oil sand faces challenges in reducing solvent content in rejects for safe atmospheric discharge and maintaining a reliable seal between the solvent processing environment and the atmosphere, especially with volatile solvents and large rock particles.
Innovation Solution
A method involving contacting oil sand with a non-aqueous solvent, screening to separate rejects, introducing rejects into a liquid bath to reduce solvent content, and transporting them through the bath to prevent solvent venting, creating a safe and reliable seal between the solvent processing environment and the atmosphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rejects are removed from the slurry for atmospheric discharge, then the screening process can proceed, but the solvent content in rejects must be reduced to safe levels before exposure to atmosphere
Solution Approach 1:
A liquid seal bath serves as an intermediary medium between the pressurized solvent processing environment and the atmosphere. The rejects are transported through this liquid seal, which allows solvent vapors to dissolve in the liquid rather than venting directly to atmosphere, thereby reducing harmful solvent content in rejects while maintaining processing productivity
2Reliability
If a seal is provided between the pressurized solvent environment and atmosphere, then solvent venting is prevented, but transporting rejects through the seal is technically challenging
Solution Approach 1:
The patent uses a hydraulic seal system where a liquid (typically water or process liquid) creates a seal barrier. Rejects are transported through this liquid seal using submersible conveyors or pneumatic conveying systems that operate within the liquid-filled sealed chamber, combining reliable sealing with effective rejects removal
3Productivity
If volatile solvent is used for extraction, then bitumen extraction efficiency is improved, but the risk of explosive conditions and solvent venting increases
Solution Approach 1:
The liquid seal bath creates an inert barrier environment that prevents volatile solvent vapors from reaching the atmosphere where they could form explosive mixtures. The liquid seal chamber maintains a controlled environment where volatile solvent is contained and its vapors are absorbed by the liquid seal, eliminating explosive risks while preserving extraction efficiency
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 effectively transports and removes rejects while preventing solvent venting to the atmosphere, enhancing safety by reducing the risk of explosive conditions and integrating solvent removal and bitumen extraction into a single process step.
Implementation Method 1
introducing the rejects stream into a liquid bath... extracting bitumen from the screened oil sand slurry
Implementation Method 2
creating a safe and reliable seal between the solvent processing environment and the atmosphere
Data Source
AI summary
The present invention provides a method for extracting bitumen from an oil sand stream, the method including at least the steps of: (a) providing an oil sand stream; (b) contacting the oil sand stream with a liquid comprising a non-aqueous solvent thereby obtaining a solvent-diluted oil sand slurry; (c) screening the solvent-diluted oil sand slurry thereby obtaining a screened oil sand slurry and a rejects stream; (d) introducing the rejects stream into a liquid bath; (e) transporting the rejects stream through the liquid bath to a space above the surface of the liquid bath; and (f) extracting bitumen from the screened oil sand slurry obtained in step (c).