Thermocatalytic Depolymerization of Mixed Plastic Waste
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Solution Overview
Problem
Current methods for recycling plastic waste are inefficient, producing lower-quality substances and being costly, and are not applicable to mixed plastic waste, leading to disposal in landfills or as thermal energy.
Innovation Solution
A thermocatalytic process involving a screw extruder to melt plastic waste, followed by depolymerization in a continuously stirred tank reactor under controlled temperature and pressure, with optional use of a depolymerization catalyst, to produce pyrolytic products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical recycling of plastic waste material is used, then recycling is achieved, but the produced substances have lower quality and the process is costly and burdensome
Solution Approach 1:
The patent applies parameter changes by transforming the plastic waste through controlled thermal and catalytic conditions (temperature, pressure, catalyst presence) to convert it into high-quality liquid fuel products, thereby improving product quality while maintaining process feasibility
Solution Approach 2:
The patent replaces mechanical recycling methods with a thermocatalytic process that uses thermal energy and catalysts to depolymerize plastic waste, substituting mechanical operations with thermal-chemical transformations to achieve higher quality products
2Ease of manufacture
If mechanical recycling of plastic waste material is used, then recycling is achieved, but the process is costly and burdensome
Solution Approach 1:
The patent replaces complex mechanical sorting and processing operations with a unified thermocatalytic conversion process that handles mixed plastic waste directly, reducing operational burden and simplifying the overall recycling workflow
3Loss of substance
If plastic waste is disposed of in landfills or used as thermal energy, then disposal is achieved, but recycling and reintroduction into production cycle is not realized
Solution Approach 1:
The patent converts the harmful waste disposal problem into a beneficial resource recovery process by transforming plastic waste into valuable liquid fuel products through thermocatalysis, thereby eliminating waste while creating useful products for reintroduction into the production cycle
4Reliability
If twin-chamber pyrolysis system operates in alternate mode for chamber cleaning, then char removal is achieved, but the amount of plastic treated per unit of time is reduced
Solution Approach 1:
The patent applies preliminary action by implementing a continuous char removal system that prevents char accumulation before it affects processing efficiency, eliminating the need for periodic chamber shutdowns and maintaining continuous plastic treatment at full capacity
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
This process effectively converts plastic waste into high-quality pyrolytic products, such as hydrocarbon fuels, reducing the need for fossil hydrocarbons and providing a more efficient and cost-effective recycling method.
Implementation Method 1
a screw extruder heated to the melting temperature of the plastic material, and melting the plastic material, thereby forming a molten plastic material
Implementation Method 2
a first depolymerization reactor, being a continuously stirred tank reactor maintained at a temperature ranging from 280 to 600° C., thereby depolymerizing the plastic material
Implementation Method 3
The resulting hot pyrolytic gases are then condensed in one or more condensers, thereby yielding a hydrocarbon distillate made from or containing straight and branched chain aliphatic, cyclic aliphatic, and aromatic hydrocarbons (pyrolytic oil)
Data Source
AI summary
A thermo-catalytic process for the depolymerizing waste plastic material and producing a pyrolytic oil, uses two agitated vessel depolymerization reactors, two condensation units, and a char handling section.