Aliphatic Hydrocarbon Recovery via Liquid-Liquid Extraction
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Solution Overview
Problem
Current processes for recovering aliphatic hydrocarbons from liquid streams containing aliphatic and aromatic hydrocarbons, and polar components from pyrolysis of waste plastics are energy-intensive and capital-expensive, with yield losses due to gas formation and solid side-products, and require costly hydrogen treatment.
Innovation Solution
A process involving liquid-liquid extraction using an organic solvent stream to separate aliphatic hydrocarbons from a liquid hydrocarbon feedstock stream, eliminating the need for hydrotreating and reducing yield loss, where the solvent stream is fed above the hydrocarbon stream in a column for effective recovery of aliphatic hydrocarbons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional separation processes are used to recover aliphatic hydrocarbons from liquid pyrolysis streams, then separation can be achieved, but energy demand and capital expenditure increase significantly
Solution Approach 1:
The invention changes the separation mechanism from thermal-based (distillation) to solvent-based (liquid-liquid extraction). By selecting appropriate solvents that selectively dissolve aromatic hydrocarbons and polar components, the process achieves effective separation at lower temperatures, dramatically reducing energy demand while maintaining high recovery efficiency of aliphatic hydrocarbons
Solution Approach 2:
The invention introduces a solvent as an intermediary substance to facilitate separation. The solvent acts as a mediator that selectively interacts with aromatic hydrocarbons and polar components, allowing aliphatic hydrocarbons to be recovered in the raffinate stream without requiring high-energy thermal separation processes
2Object-generated harmful factors
If hydrotreating is applied to treat the liquid stream, then aromatic hydrocarbons can be removed, but capital expenditure and operational costs increase
Solution Approach 1:
The invention directly extracts and removes aromatic hydrocarbons and polar components from the liquid pyrolysis stream using liquid-liquid extraction. By feeding the solvent stream above the hydrocarbon stream in a extraction column, aromatics are selectively transferred to the solvent phase, achieving removal without requiring complex hydrotreating units and their associated high capital expenditure
Solution Approach 2:
The invention replaces the mechanical/chemical system of hydrotreating (requiring high-pressure hydrogen, catalysts, and complex reactors) with a simpler liquid-liquid extraction system. This substitution eliminates the need for expensive hydrotreating equipment while achieving the same goal of removing harmful aromatic components
3Manufacturing precision
If distillation is used to separate hydrocarbon fractions, then separation can be achieved, but yield loss occurs due to gas formation and solid side-products
Solution Approach 1:
The invention utilizes liquid-liquid phase separation instead of vapor-liquid phase separation (distillation). By operating entirely in the liquid phase at ambient or mild temperatures, the process avoids thermal cracking that produces gas formation and solid coke deposits, thereby minimizing yield loss while achieving precise separation of hydrocarbon fractions
Solution Approach 2:
The invention performs preliminary extraction of aromatics and polar components before any thermal processing. By removing these problematic components first through liquid-liquid extraction, the subsequent processing of the aliphatic-rich stream experiences minimal yield loss from gas formation or solid side-product formation
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 process reduces energy demand and capital expenditure, lowers feed costs to steam crackers, and minimizes feed degradation, achieving efficient recovery of aliphatic hydrocarbons without the need for hydrogen treatment, while also reducing fouling components that cause issues in steam cracking equipment.
Implementation Method 1
contacting at least a portion of the liquid hydrocarbon feedstock stream with at least a portion of the first solvent stream; and recovering at least a portion of the aliphatic hydrocarbons by liquid-liquid extraction of aromatic hydrocarbons and/or polar components with organic solvent
Data Source
AI summary
The invention relates to a process for the recovery of aliphatic hydrocarbons from a liquid hydrocarbon feedstock stream, which comprises aliphatic hydrocarbons and additionally comprises aromatic hydrocarbons and/or polar components, said process comprising the steps of: feeding the liquid hydrocarbon feedstock stream to a first column; feeding a first solvent stream which comprises an organic solvent to the first column at a position which is higher than the position at which the liquid hydrocarbon feedstock stream is fed; contacting at least a portion of the liquid hydrocarbon feedstock stream with at least a portion of the first solvent stream; and recovering at least a portion of the aliphatic hydrocarbons by liquid-liquid extraction of aromatic hydrocarbons and/or polar components with organic solvent, resulting in a stream comprising recovered aliphatic hydrocarbons and optionally organic solvent and a bottom stream from the first column comprising organic solvent and aromatic hydrocarbons and/or polar components.