Pyrolysis Oil Purification with Immiscible Polar Solvent Extraction
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Solution Overview
Problem
Existing methods for purifying pyrolysis oil from plastic waste do not effectively reduce the content of heteroatoms, unsaturated hydrocarbon compounds, and other contaminants, particularly when mixed with other types of waste, which can hinder its use as a feedstock for steam-cracking processes.
Innovation Solution
A method involving a polar solvent immiscible with pyrolysis oil is used to extract polar compounds and unsaturated hydrocarbons, achieving a recovery rate of at least 0.95, resulting in a raffinate with reduced contaminants, allowing direct use in steam-cracking without further solvent removal steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional solvent extraction methods are used to purify pyrolysis oil, then some polar compounds are removed, but the recovery rate of the solvent is low (less than 0.95) requiring additional water extraction steps
Solution Approach 1:
The patent changes the key parameter of solvent selection to a polar solvent immiscible with pyrolysis oil (such as formamide, N-methylformamide, N,N-dimethylformamide, propylene carbonate, or ethylene carbonate). This parameter change achieves both high purification quality and high solvent recovery rate (≥0.95), eliminating the need for additional water extraction steps and thereby reducing process complexity
Solution Approach 2:
The patent extracts polar compounds and unsaturated hydrocarbon compounds from pyrolysis oil using a specifically selected polar immiscible solvent. The extraction process removes contaminants including heteroatoms (oxygen, nitrogen, sulfur, metals, halides) and unsaturated compounds (aromatics and dienes), achieving effective purification in a single step
2Reliability
If pyrolysis oil contains high levels of heteroatoms and unsaturated compounds, then the feedstock quality for steam-cracking is poor, but conventional extraction methods cannot sufficiently reduce these contaminants
Solution Approach 1:
The patent changes the solvent selection parameter to polar solvents immiscible with pyrolysis oil, which have specific chemical properties that enable effective removal of heteroatoms and unsaturated compounds. This parameter change achieves superior contaminant reduction efficiency, producing high-quality feedstock for steam-cracking processes
Solution Approach 2:
The polar immiscible solvent acts as an intermediary that selectively interacts with and extracts polar compounds and unsaturated hydrocarbons from the pyrolysis oil. The solvent mediates the separation process, transferring contaminants from the oil phase to the solvent phase, thereby purifying the feedstock for steam-cracking
3Loss of substance
If additional water extraction steps are added to remove solvent, then solvent recovery is improved, but the process becomes more resource-intensive and complex
Solution Approach 1:
The patent changes the solvent property parameter to immiscibility with pyrolysis oil, which enables the solvent to be easily separated and recovered in a single extraction step with a recovery rate ≥0.95. This parameter change eliminates the need for additional water extraction steps, thereby reducing resource consumption and process complexity while maintaining high solvent recovery
Solution Approach 2:
The patent extracts and recovers the polar immiscible solvent in a single extraction operation. The solvent, being immiscible with pyrolysis oil, forms a separate phase that can be easily separated and reused, achieving high solvent recovery without requiring additional water extraction steps and thus reducing resource intensity
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 achieves significant reduction of heteroatoms (oxygen, nitrogen, sulfur, metals, and halides) and unsaturated hydrocarbons, preparing a pyrolysis oil raffinate suitable for steam-cracking with reduced contaminants, enhancing the efficiency and effectiveness of the steam-cracking process.
Implementation Method 1
contacting the pyrolysis oil with a polar extraction solvent which is immiscible with the pyrolysis oil, recovering an extract and an raffinate which are immiscible with each other, the extract containing the extraction solvent and at least one part of the polar compounds
Data Source
AI summary
The invention relates to a method for purifying a pyrolysis oil originating from the pyrolysis of waste including plastics by liquid/liquid extraction. This extraction is performed by means of a polar solvent that is immiscible with pyrolysis oil, for which a recovery rate is obtained greater than or equal to 0.95, this recovery rate being defined as the ratio of the extract volume over the initial volume of solvent, this extract being a phase containing the solvent which is immiscible with pyrolysis oil, recovered after agitation then decantation of a mixture of one part by volume of solvent with twenty-five parts by volume of pyrolysis oil at atmospheric pressure and at a temperature of 20° C.