Integrating Slurry Hydrocracking and Solvent Deasphalting
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Solution Overview
Problem
Current processes struggle to effectively separate heavy hydrocarbons into paraffinic feed for fixed-bed catalytic hydroprocessing or FCC, as multi-ring aromatics are not adequately separated, leading to catalyst deactivation and increased hydrogen consumption.
Innovation Solution
The process involves solvent deasphalting to extract a DAO stream rich in saturated compounds and an asphaltene stream rich in aromatic compounds, followed by slurry hydrocracking and further deasphalting to separate aromatics from paraffins, allowing for the separation of light VGO from heavy VGO without a vacuum column and recycling of HVGO to control mesophase production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional distillation and fixed-bed hydroprocessing are used, then heavy hydrocarbons are processed, but multi-ring aromatics are not adequately separated leading to catalyst deactivation and increased hydrogen consumption
Solution Approach 1:
The process segments the heavy hydrocarbon feed into two distinct streams through solvent deasphalting: a DAO stream containing paraffinic components suitable for fixed-bed hydroprocessing, and an asphaltene stream containing aromatic components including multi-ring aromatics suitable for slurry hydrocracking. This segmentation prevents multi-ring aromatics from entering the fixed-bed reactor where they would deactivate the catalyst, while also avoiding unnecessary hydrogen consumption on aromatic components that are better processed via slurry hydrocracking.
Solution Approach 2:
The process changes the processing parameters by using solvent deasphalting to alter the composition and properties of the feed streams before they enter the hydroprocessing units. By adjusting the solvent-to-feed ratio and extraction conditions, the process optimizes the separation between paraffinic and aromatic components, ensuring that each stream is appropriately prepared for its designated processing route.
2Manufacturing precision
If vacuum column is used to separate VGO from pitch, then separation is achieved, but large operating expenses are incurred
Solution Approach 1:
The process performs preliminary separation of heavy hydrocarbons into paraffinic and aromatic streams using solvent deasphalting before the slurry hydrocracking step. This preliminary action removes the need for a vacuum column downstream to separate VGO from pitch, as the aromatic-rich stream from slurry hydrocracking is already separated from the paraffinic VGO. This eliminates the energy-intensive vacuum distillation step and reduces operating expenses while maintaining separation efficiency.
3Reliability
If heavy VGO is recycled to SHC reactor, then coking is prevented, but process complexity increases
Solution Approach 1:
The process extracts and removes multi-ring aromatic components from the heavy VGO stream through solvent deasphalting before recycling to the slurry hydrocracking reactor. By taking out the problematic aromatic components that contribute to coking, the recycled stream has improved stability and reduced coking tendency, maintaining reactor operation stability while simplifying the overall process by reducing the need for complex coking prevention strategies.
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 enables efficient separation of hydrocarbons, minimizing catalyst deactivation and hydrogen consumption, and allows for optimal processing of heavy hydrocarbons into lighter products, improving the yield and reducing operating expenses.
Implementation Method 1
SDA separates hydrocarbons according to their solubility in a liquid solvent, as opposed to volatility in distillation. Lower molecular weight and most paraffinic components are preferentially extracted.
Implementation Method 2
In SHC, these liquid feedstocks are mixed with hydrogen and solid catalyst particles, e.g., as a particulate metallic compound such as a metal sulfide, to provide a slurry phase.
Implementation Method 3
SHC produces naphtha, diesel, gas oil such as VGO, and a low-value, refractory pitch stream
Data Source
AI summary
Solvent deasphalting (SDA) is used to prepare a heavy hydrocarbon feed for further upgrading. An overhead deasphalted oil (DAO) stream is prepared for catalytic upgrading and an asphaltene stream is prepared for slurry hydrocracking (SHC). SHC product can be further deasphalted and the DAO can be separated from solvent in an upstream extraction column.