Pyrolysis Oil Purification by Diene Polymerization
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Solution Overview
Problem
The pyrolysis plastic oil obtained from plastic pyrolysis contains high levels of dienes, which react easily to form gums and act as coke precursors, preventing its direct use in steam crackers, necessitating a purification process to remove these components.
Innovation Solution
A process involving cationic polymerization of pyrolysis plastic oil in the presence of an acidic catalyst to convert dienes into heavier oligomeric products, followed by neutralization, washing, and separation to remove impurities, allowing further conversion into valuable resins or use in steam cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If waste plastics are used as feedstock for oil production, then resource utilization is improved, but contamination with metals, sulfur, and nitrogen compounds increases
Solution Approach 1:
The patent extracts and removes harmful contaminants (metals, sulfur, nitrogen compounds) from the waste plastic feedstock through dedicated purification units. The system separates these harmful substances from the plastic material stream before pyrolysis, preventing them from contaminating the resulting oil product.
Solution Approach 2:
The patent introduces an intermediary purification system between the waste plastic feedstock and the pyrolysis process. This intermediary stage includes washing units and filtration systems that act as mediators to remove contaminants before the main conversion process, protecting the downstream oil production from contamination.
2Quantity of substance
If conventional pyrolysis is used for plastic decomposition, then oil production is achieved, but the process is energy-intensive and produces unwanted by-products
Solution Approach 1:
The patent changes the operational parameters of the pyrolysis process, specifically operating at lower temperatures and controlled atmospheric conditions. By optimizing parameters such as heating rate, residence time, and oxygen partial pressure, the system achieves efficient plastic decomposition with reduced energy input and minimized unwanted by-products.
Solution Approach 2:
The patent implements a continuous pyrolysis process where waste plastics are continuously fed and converted to oil. The system maintains continuous operation with integrated separation and purification units running simultaneously, ensuring uninterrupted oil production and efficient energy utilization without idle cycles.
3Manufacturing precision
If multiple purification steps are implemented, then oil quality is improved, but process complexity increases
Solution Approach 1:
The patent combines multiple purification functions into integrated units. The washing unit, filtration system, and separation processes are merged into a unified purification train that operates sequentially in one compact system. This integration maintains comprehensive oil quality improvement while reducing the overall footprint and operational complexity compared to separate standalone units.
4Quantity of substance
If waste plastics containing sulfur and nitrogen are processed, then feedstock availability is improved, but environmental pollution increases
Solution Approach 1:
The patent converts the harmful sulfur and nitrogen compounds present in waste plastics into beneficial applications. These contaminants are extracted and concentrated to produce sulfuric acid and other chemical products that can be sold as commercial by-products. This approach transforms environmental pollutants into valuable resources, reducing pollution while maintaining feedstock flexibility.
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, enabling the pyrolysis plastic oil to be used in steam crackers and producing valuable resins, while also allowing the production of olefins and aromatics through steam cracking.
Implementation Method 1
decomposition of plastic material in a first catalyst bed at a temperature of 300°C to 500°C in an atmosphere of substantially zero oxygen content
Implementation Method 2
contacting the effluent from the first catalyst bed with a polymerization catalyst to polymerize olefinic hydrocarbons present in the effluent
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 for instance the pyrolysis of waste plastics via the polymerization of dienes prior to further treatments.