Solvent Extraction for Steam Cracking Feedstock
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Solution Overview
Problem
Heavy fractions used directly in thermal steam cracking processes result in lower yields of desirable olefins like ethylene and propylene, and produce more undesirable byproducts such as fuel oil, highlighting the need for a pretreatment process to upgrade the quality of feedstock before steam cracking.
Innovation Solution
A method involving solvent extraction to remove aromatics and naphthenes from hydrocarbon feedstocks, producing a refined paraffin-rich stream for steam cracking, with specific composition ranges for optimal olefin yields, and subsequent processing in a steam cracking unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If heavy fractions are used directly in thermal steam cracking processes, then the process complexity is reduced, but the olefin yield decreases and undesirable byproducts increase
Solution Approach 1:
The patent applies preliminary action by performing solvent extraction before steam cracking to remove aromatics and naphthenes from heavy fractions. This pre-treatment prepares the feedstock in advance, transforming it into a paraffin-rich stream that will yield higher olefin production during subsequent cracking, thereby resolving the contradiction between simplified process and improved productivity.
Solution Approach 2:
The patent employs extraction by using a polar solvent to selectively remove aromatics and naphthenes from the heavy fraction feedstock. This separation extracts the components that would otherwise reduce olefin yield and create undesirable byproducts, allowing the steam cracking process to operate on a refined feedstock with superior cracking properties.
2Productivity
If solvent extraction is used to remove aromatics and naphthenes, then olefin yield increases, but the device complexity and capital cost increase
Solution Approach 1:
The patent uses a polar solvent as an intermediary substance to facilitate the separation of aromatics and naphthenes from the heavy fraction. The solvent acts as a mediator that selectively interacts with the unwanted components, enabling their removal without requiring complex mechanical separation equipment, thus achieving improved olefin yield with moderate additional complexity.
3Productivity
If aromatics and naphthenes are removed from feedstock, then ethylene and propylene production increases, but heavier liquid product formation increases
Solution Approach 1:
The patent removes aromatics and naphthenes through solvent extraction before steam cracking. By taking out these components in advance, the process achieves higher ethylene and propylene yields from the remaining paraffinic feedstock, while the extracted components can be processed separately or used as fuel, thereby managing the quantity of heavier liquid products.
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
Enhances olefin yields in steam cracking units by reducing aromatics and naphthenes content, leading to increased production of ethylene and propylene while minimizing the formation of heavier liquid products, without the need for hydrogen or capital-intensive hydroprocessing units.
Implementation Method 1
contacting said hydrocarbon feedstock with a solvent at a dosage effective to remove aromatics and naphthenes from said feedstock
Implementation Method 2
processing said refined feedstock in a steam cracking process
Data Source
AI summary
The present invention relates to a method for producing high-quality feedstock for a steam cracking process, said method comprising the following steps: i) providing a hydrocarbon feedstock; ii) contacting said hydrocarbon feedstock with a solvent at a dosage effective to remove aromatics and naphthenes from said feedstock forming a refined feedstock and one or more aromatics and naphthenes containing streams; iii) processing said refined feedstock in a steam cracking process.