Three-Section Asphaltene Separator with Pumparound
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Solution Overview
Problem
Current solvent deasphalting processes face challenges in efficiently separating precipitated asphaltene solids from heavy hydrocarbon mixtures, particularly with Canadian Bitumen, due to issues like plugging, high solvent requirements, and low recovery rates, leading to economic inefficiencies and equipment fouling.
Innovation Solution
A novel three-section solid asphaltene separator design with a pumparound scheme that integrates solvent injection and counter-current flow within a single vessel, reducing the need for internal mass transfer devices and minimizing solvent usage, allowing for effective separation of oil-free solid asphaltenes and high DAO recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solvent deasphalting processes are used to separate asphaltene solids from heavy hydrocarbon mixtures, then separation is achieved, but equipment plugging and fouling occur due to solid asphaltene accumulation
Solution Approach 1:
The separator is divided into three distinct vertical sections (upper, middle, lower) with different functions: the upper section handles liquid-liquid separation, the middle section facilitates solid settling, and the lower section manages solvent recovery. This segmentation allows each section to be optimized for its specific function, preventing solid accumulation in critical areas and maintaining continuous operation.
Solution Approach 2:
The invention transitions from horizontal or single-zone separation approaches to a vertical three-section configuration. This dimensional change enables counter-current flow patterns and gravitational separation of solids in the middle section, effectively removing asphaltene solids from the process stream before they can cause plugging downstream.
2Productivity
If high solvent to oil ratios are used in solvent deasphalting, then extraction efficiency improves, but operational costs and solvent requirements increase
Solution Approach 1:
The pumparound scheme creates a feedback loop where solvent is continuously circulated from the lower section, heated, and returned to the upper section. This recycles solvent within the system, reducing fresh solvent requirements and maintaining extraction efficiency without proportionally increasing solvent consumption.
Solution Approach 2:
The process recovers solvent from the lower section where it has contacted the asphaltene-rich stream, separates it from solids, and returns it to the upper section for reuse. This recovery mechanism reduces the quantity of fresh solvent needed while maintaining high extraction efficiency.
3Manufacturing precision
If internal mass transfer devices are used in the separator, then separation performance improves, but device complexity and maintenance requirements increase
Solution Approach 1:
The middle section is designed to utilize the natural gravitational settling of solid asphaltenes and the density difference between liquid phases to achieve separation without mechanical agitators or complex internal devices. The system serves itself through carefully controlled flow patterns and vertical arrangement, reducing device complexity while maintaining separation performance.
4Ease of manufacture
If spray driers are used to dry asphaltene particles, then solid product is produced, but the process becomes infeasible when asphaltenes are in solid form at operating temperature due to nozzle plugging
Solution Approach 1:
The invention extracts and removes solid asphaltene particles from the liquid stream in the middle section through gravitational settling before the mixture reaches the drying stage. By taking out solids early in the process, the remaining liquid stream is free of particles that would plug spray drier nozzles, making the subsequent drying operation reliable and feasible.
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 design achieves over 99% DAO recovery with less than 5% DAO content in the asphaltene product, reducing solvent requirements and operational costs while maintaining reliable continuous operation, even with high-asphaltene-rich feedstocks like Canadian Bitumen.
Implementation Method 1
a first section at an upper portion of the separator, a second section at a middle portion of the separator, and a third section at a lower portion of the separator
Implementation Method 2
separating precipitated asphaltene solids from solvent/heavy hydrocarbon mixtures
Implementation Method 3
pumparound scheme that integrates solvent injection and counter-current flow
Implementation Method 4
Heating the solvent from the lower section to a temperature above the feedstock temperature prior to mixing with the feedstock in the upper section
Implementation Method 5
provides sufficient solvent flow to the upper section to provide additional mass transfer
Implementation Method 6
Mixing the heated solvent with the feedstock in the upper section
Data Source
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AI summary
An apparatus and process is provided for improved asphaltene separation from heavy hydrocarbon or bitumen with low process complexity through mass transfer using solvent and counter-current flows, with three sections: an upper DAO/solid-asphaltene separation zone, a middle solvent mixing and segregation zone, and a bottom clarification zone. Solvent mixed with heavy hydrocarbon forms a process feed introduced to the process vessel's upper zone and exposed to counter-current solvent removing DAO from solid asphaltene particles in the feed, the particles fall through the middle zone and are mixed with introduced solvent, which introduced solvent segregates DAO-rich solution in the upper zone (for extraction from that zone) from solvent-rich mixtures in the middle mixing and lower clarification zones. Solvent flows and precipitate movement are controlled to optimize mass transfer in process, resulting in high DAO recovery and dry, solid asphaltene product.