Polyolefin Extraction from Waste Using Non-Polar Solvents
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Solution Overview
Problem
Current polymer recycling methods face challenges such as high energy consumption, CO2 emissions, and the inability to produce virgin-like polymers efficiently, particularly in continuous processes, and struggle with recycling polymers from waste with low content and high contaminant levels, limiting their use in high-quality applications like food and drug packaging.
Innovation Solution
A process involving the use of a non-polar solvent to dissolve polyolefins from waste materials at specific temperature and pressure conditions, followed by separation and solvent removal, allowing for the extraction of high-purity polyolefins that can be reused in various recycling processes, including mechanical, chemical, and pyrolysis recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If thermal degradation methods (pyrolysis, gasification) are used to recycle plastics, then polymer material can be recovered, but energy consumption is significantly higher and CO2 emissions occur
Solution Approach 1:
The patent changes the physical-chemical parameters by using supercritical or subcritical water as a solvent instead of thermal degradation. This allows polymer extraction at lower temperatures (subcritical conditions) or at critical points, avoiding high-energy thermal breakdown while still achieving effective polymer recovery from waste plastic materials.
Solution Approach 2:
The patent introduces water as an intermediary solvent to extract polymers from waste plastic. This intermediary medium enables selective dissolution and extraction of polymers without requiring direct thermal degradation, thus reducing energy consumption and avoiding CO2 emissions associated with pyrolysis and gasification processes.
2Quantity of substance
If mechanical recycling with separation steps is used, then polymer type enrichment is achieved, but product quality remains relatively poor and does not allow food contact or high performance applications
Solution Approach 1:
The patent changes the extraction parameters by using supercritical or subcritical water to achieve complete polymer dissolution and high-purity extraction. This parameter change enables the production of virgin-like polymer quality suitable for food contact and high performance applications, overcoming the limitations of conventional mechanical recycling.
Solution Approach 2:
The patent utilizes phase transitions of water (liquid-liquid phase separation under supercritical or subcritical conditions) to achieve clean polymer extraction. The phase transition allows for complete separation of polymer from contaminants, producing high-purity polymer material that meets food contact and high performance application requirements.
3Stability of the object's composition
If advanced physical or solvent based recycling is used, then original molecular structure is preserved, but high pressure processing is required which needs experienced staff and causes high investment costs
Solution Approach 1:
The patent changes the pressure parameters by operating at supercritical or subcritical water conditions, which can be achieved at lower pressures compared to conventional high-pressure solvent recycling. This parameter change maintains molecular structure preservation while reducing the complexity and investment costs associated with high-pressure processing equipment.
Solution Approach 2:
The patent uses water, an abundant and inexpensive solvent, instead of expensive high-pressure solvents. This substitution maintains the ability to preserve molecular structure while significantly reducing equipment investment costs and operational complexity, as water requires no special high-pressure handling infrastructure.
4Productivity
If continuous high pressure process is designed, then productivity is improved, but it is generally difficult to design continuously operated high pressure process
Solution Approach 1:
The patent changes the operating parameters to supercritical or subcritical water conditions, which enable continuous processing at more manageable pressures. This parameter change facilitates the design of continuous processing systems while reducing the difficulty compared to conventional high-pressure processes, as the equipment requirements and safety considerations are reduced.
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 method enables the efficient extraction of high-purity polyolefins from waste materials, reducing energy consumption and environmental impact, and allows for the production of virgin-like polymers suitable for high-quality applications, including food and drug packaging, while being adaptable to both continuous and discontinuous processes.
Implementation Method 1
contacting the polymer-containing waste material with a non-polar solvent (S) comprising at least one hydrocarbon, optionally halogenated hydrocarbon, having from 4 to 10 carbon atoms, to form a composition (C)
Implementation Method 2
heating the composition (C) at a dissolution temperature (T) in the range of 135 to 200° C. and a pressure (P) in the range of 0.1 to 5 MPa for a period of from 5 min to 5 h (M)
Implementation Method 3
solidification of the polymer is caused by the preferably complete separation of the solvent from the solidified polymer by thermal unit operations (evaporation, drying etc.)
Data Source
AI summary
The present invention relates to a process for extracting polymers, preferably polyolefins, from polymer-containing waste material comprising the steps of: providing polymer-containing waste material comprising polyolefin material; contacting the polymer-containing waste material with a non-polar solvent (8) comprising at least one hydrocarbon, optionally halogenated hydrocarbon, having from 4 to 10 carbon atoms, to form a composition (C); heating the composition (C) at a dissolution temperature (T) in the range of 135 to 200° C. and a pressure (P) in the range of 0.1 to 5 MPa for a period of from 5 min to 5 h (M), to obtain a solution comprising the solvent (S) and the polyolefin material dissolved in the solvent (S), and an undissolved material (U); separating the undissolved material (U) from the solution; separating the polyolefin material from the solution, and optionally separating the solvent (S) from the solution.