Hydrocarbon Fluid Purification from Waste Plastic Pyrolysis
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Solution Overview
Problem
Pyrolysis oils derived from waste plastic contain high levels of contaminants such as chlorides, metals, and olefins, making them unsuitable for conventional refinery processes due to feed specifications and potential equipment damage.
Innovation Solution
A method involving washing with a polar solvent and contacting with adsorbents to remove contaminants, followed by hydroprocessing to hydrogenate olefins and diolefins, resulting in a hydrocarbon fluid with reduced contaminant levels, suitable for integration into conventional refining methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pyrolysis oil is used directly as feedstock in conventional refinery processes, then the process can utilize waste plastic feedstock, but the high contaminant levels (chlorides, metals, olefins) cause equipment damage and process failures
Solution Approach 1:
The patent applies preliminary action by implementing a contaminant removal process before the pyrolysis oil enters conventional refinery processes. The method includes washing with polar solvents to remove chlorides and metals, followed by adsorption using activated carbon or molecular sieves to remove remaining contaminants and olefins. This preliminary treatment ensures the feedstock meets specification requirements before processing, preventing equipment damage while maintaining the ability to utilize waste plastic feedstock.
Solution Approach 2:
The patent uses intermediary substances to bridge the gap between contaminated pyrolysis oil and conventional refinery processes. Polar solvents (such as water or alcohols) serve as intermediaries to extract chlorides and metals during washing. Activated carbon and molecular sieves act as intermediary adsorbents to remove remaining contaminants and olefins. These intermediaries enable the transition from high-contaminant feedstock to specification-compliant feedstock without direct contact between contaminants and refinery equipment.
2Manufacturing precision
If extensive sorting and cleaning processes are implemented to meet feed specifications, then contaminant levels are reduced, but the process complexity and cost increase significantly
Solution Approach 1:
The patent applies parameter changes by transforming the chemical and physical properties of contaminants through controlled chemical reactions and phase changes. Washing with polar solvents changes the solubility parameters of chlorides and metals, allowing their extraction into the polar phase. Adsorption processes change the concentration parameters by transferring contaminants from the liquid phase to the adsorbent phase. Hydroprocessing changes the chemical structure of olefins by hydrogenation. These parameter changes achieve high feedstock purity through relatively simple unit operations rather than extensive mechanical sorting and cleaning.
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
The method effectively reduces contaminant levels in pyrolysis oils, enabling their use in producing high-purity hydrocarbon fluids with low olefin content, metals, chlorine, and sulfur, suitable for various applications, including specialty fluids and fuels.
Implementation Method 1
subjecting at least a portion of the first hydrocarbon feed stream to a washing step with a polar solvent (thereby reducing the content of polar contaminants in said first hydrocarbon feed stream)
Implementation Method 2
contacting at least a portion of the first hydrocarbon feed stream with one or more adsorbents, wherein the adsorbents are suitable for removing one or more contaminants selected from water, metals, chlorides, nitrogen-containing compounds, oxygenates, and phosphorous-containing compounds
Implementation Method 3
at least a part of the first hydrocarbon fluid, optionally blended with a second hydrocarbon feed stream, is subjected to hydroprocessing to hydrogenate olefins and diolefins in the first hydrocarbon fluid
Implementation Method 4
a first hydrocarbon feed stream is provided, comprising material obtained from the pyrolysis of plastic waste
Data Source
AI summary
Provided herein is a method for producing a hydrocarbon fluid from waste plastic feedstock, comprising (a) providing a first hydrocarbon feed stream, wherein at least 50 wt % off said first hydrocarbon feed stream is obtained from pyrolysis of plastic waste; (b) removing contaminants from said first hydrocarbon feed stream using a washing step with a polar solvent and/or contacting the stream with one or more adsorbents; thereby obtaining a first hydrocarbon fluid; and (c) hydrogenation of olefins and diolefins in said first hydrocarbon fluid; thereby obtaining a hydroprocessed hydrocarbon fluid containing less than 0.1 wt % olefins; a total amount of Nmetals selected from mercury, lead, and iron below 5 wppm; less than 5 wppm of chlorine and fluorine; and less than 5 wppm of sulfur.