Pyrolysis Oil Purification via Diene Polymerization and Neutralization
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Solution Overview
Problem
Pyrolysis plastic oil obtained from waste plastics contains high levels of dienes, which react easily and form gums, making it unsuitable for direct use in steam crackers, and existing purification methods are inadequate for removing these impurities effectively.
Innovation Solution
A process involving cationic polymerization with an acidic catalyst, followed by neutralization with a basic compound, and subsequent separation to remove dienes from pyrolysis plastic oil, allowing further conversion in steam crackers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If waste plastics are pyrolyzed to produce oil, then energy recovery is achieved, but the oil contains harmful impurities (aromatic hydrocarbons, nitrogen compounds, sulfur compounds) that require complex purification
Solution Approach 1:
The patent extracts and removes specific harmful impurities (aromatic hydrocarbons, nitrogen compounds, sulfur compounds) from the pyrolysis oil through targeted chemical treatment steps, separating these contaminants from the useful oil product to simplify the overall purification process while maintaining effectiveness
Solution Approach 2:
The patent introduces basic compounds (such as calcium oxide, calcium hydroxide, or calcium carbonate) as intermediary substances that facilitate the removal of harmful impurities. These basic compounds act as mediators that react with acidic impurities to form removable compounds, simplifying the purification process compared to direct complex treatment methods
2Quantity of substance
If conventional purification methods are used, then some impurities are removed, but the process requires multiple steps and high costs
Solution Approach 1:
The patent combines multiple purification functions (removal of aromatic hydrocarbons, nitrogen compounds, and sulfur compounds) into a single integrated treatment step using basic compounds. This merging of functions reduces the number of separate purification steps required while achieving comprehensive impurity removal and maintaining high productivity
Solution Approach 2:
The patent changes the chemical environment parameters by introducing basic compounds that alter the pH and chemical reactivity conditions. This parameter change enables simultaneous removal of multiple types of impurities through chemical reactions, improving purification efficiency without requiring multiple sequential steps
3Quantity of substance
If multiple purification steps are implemented, then oil quality improves, but processing time and cost increase
Solution Approach 1:
The patent performs preliminary chemical treatment by adding basic compounds to the pyrolysis oil before final processing. This preliminary action pre-reacts with and neutralizes harmful impurities, preparing the oil for more efficient final purification and reducing the time required for subsequent processing steps
Solution Approach 2:
The patent converts harmful acidic impurities (nitrogen compounds, sulfur compounds, aromatic hydrocarbons) into beneficial or removable forms through reaction with basic compounds. The harmful substances are transformed into neutral or precipitable compounds that can be easily separated, improving oil quality while reducing processing time compared to conventional multi-step methods
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 process effectively reduces diene content to less than 5.0 wt.%, enabling the pyrolysis plastic oil to be used in steam crackers and producing valuable olefins and aromatics.
Implementation Method 1
the basic compound and the impurities are contacted with each other to react, thereby removing the impurities from the pyrolysis oil
Implementation Method 2
the porous material and the pyrolysis oil are contacted with each other to adsorb the impurities from the pyrolysis oil
Data Source
Figure 1
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AI summary
The disclosure relates to the purification and treatment of oil produced from the liquefaction of waste polymer like for instance the pyrolysis of waste plastics via the polymerization of dienes prior to further treatments.