Plastic Waste Recycling Flow for Mixed 2D and 3D Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing recycling processes struggle to effectively process highly contaminated and mixed plastic waste, resulting in low recyclate quality and limited recycling rates, with a significant portion being thermally recycled and not meeting the demand for high-quality recyclates.
Innovation Solution
A plastic recycling method involving washing, shredding, and density-based separation of plastic waste mixtures, including hydrocyclones and wind sifters, to separate 2D and 3D materials, allowing for higher yield and quality of recyclates by adjusting to fluctuating material proportions and densities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing recycling processes are used to process heavily contaminated and mixed plastic waste, then the recycling infrastructure can handle some plastic waste, but the recycling rate remains low and the quality of recyclates is poor
Solution Approach 1:
The patent divides the plastic waste stream into separate fractions based on density (light fraction and heavy fraction) and further separates 2D materials from 3D materials. This segmentation allows each fraction to be processed separately, improving both the recycling rate and the quality of recyclates by preventing contamination between different material types.
Solution Approach 2:
The patent extracts and removes contaminants from the plastic waste stream through washing processes and separation techniques. By taking out contaminants early in the process, the patent enables higher quality recyclates to be produced from what would otherwise be unsuitable for recycling.
2Productivity
If pre-separation of certain plastic types is carried out at the beginning of the process, then some sorting is achieved, but the recycling quota is limited because separated plastics are mostly sent for thermal utilization
Solution Approach 1:
Instead of separating plastics at the beginning and discarding them for thermal utilization, the patent inverts the approach by collecting all plastic waste together, washing it thoroughly, and then separating it into recyclable fractions. This inversion enables a much higher recycling quota by processing previously discarded materials.
Solution Approach 2:
The patent performs preliminary washing and cleaning of the entire plastic waste stream before separation. This preliminary action removes contaminants that would otherwise prevent effective separation and reduce recycling quality, enabling higher recycling quotas from the same material stream.
3Productivity
If complex dry-mechanical separation steps such as ballistic separators or NIR sorters are used, then some plastic sorting is achieved, but films, bags and trays cannot be properly cleaned and separated from other plastics
Solution Approach 1:
The patent uses water as an intermediary medium to facilitate the separation of 2D materials from 3D materials. The washing process serves as an intermediary step that enables subsequent separation techniques to work more effectively, achieving better separation quality than dry-mechanical methods alone.
Solution Approach 2:
The patent employs hydraulic principles in the washing and separation processes, using water flow to separate materials based on density and physical properties. This hydraulic approach enables better separation of films, bags, and trays from other plastics compared to dry-mechanical separation methods.
4Device complexity
If plastic waste mixtures are processed without proper separation, then processing is simpler, but large parts of the waste are lost for recycling and must be recovered for energy only
Solution Approach 1:
The patent segments the plastic waste into valuable recyclable fractions and minor contaminant fractions. This segmentation enables most of the plastic waste to be recycled rather than lost, while keeping the processing system manageable through systematic separation techniques.
Solution Approach 2:
The patent recovers plastic materials that would otherwise be discarded for energy recovery. Through improved separation and washing techniques, the patent enables recovery of high-quality recyclates from waste streams that were previously unsuitable, reducing material loss and increasing recycling rates.
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 a significantly higher yield and quality of recyclates, enabling the recovery of various polymer grades and meeting the demand for high-quality recyclates, particularly from difficult-to-recycle material streams, while minimizing thermal recycling and enhancing recycling rates.
Implementation Method 1
Density-based separating the plastic waste mixture stream into at least two fractions, wherein the separation is performed in response to a predeterminable density separation cut
Data Source
AI summary
A plastic recycling method for processing plastic waste, including providing a plastic waste mixture stream having, on the one hand, a variable proportion of 2D material and a variable proportion of 3D material and, on the other hand, an inhomogeneous density distribution, the proportions varying over time. Washing both proportions of the plastic waste mixture stream together. Shredding both proportions of the plastic waste mixture stream together while supplying a cleaning fluid. Density-based separation of the plastic waste mixture stream into at least two fractions, wherein the separation is performed as a function of a predeterminable density separation cut; and for at least one of the separated fractions: separating the fraction of 2D material and the fraction of 3D material from each other.