Polypropylene Solvent Recycling Under Negative Pressure
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Solution Overview
Problem
Current plastic recycling processes are inefficient and environmentally harmful, particularly for polypropylene, leading to persistent environmental problems and high recycling costs.
Innovation Solution
A plastic recycling process involving mixing polypropylene with a solvent, heating and stirring to dissolve the plastic, followed by separation in a negative pressure environment to recover the plastic ingredient, using reusable solvents and non-solvents to enhance recovery rates and reduce environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional plastic recycling methods (melting regeneration or pyrolysis) are used, then plastic waste can be processed, but the recovery rate is low and environmental problems persist
Solution Approach 1:
The patent changes the physical-chemical parameters by introducing a specific solvent system and controlling temperature (80-140°C) to enable selective dissolution of polypropylene, achieving high recovery rates while avoiding harmful environmental factors associated with conventional methods
Solution Approach 2:
The patent uses a solvent as an intermediary substance to facilitate the separation and recovery of plastic ingredients. The solvent temporarily holds the dissolved plastic components, allowing for clean separation and high-quality recovery without direct harmful processing
2Speed
If heating temperature is increased to accelerate dissolution, then processing speed increases, but solvent evaporation and energy consumption increase
Solution Approach 1:
The patent optimizes the temperature parameter to a specific range (80-140°C) that balances dissolution speed with energy efficiency. This controlled temperature range accelerates dissolution without causing excessive solvent evaporation or energy waste
Solution Approach 2:
The patent maintains continuous heating and stirring throughout the dissolution process to ensure uniform and efficient dissolution. This continuous action prevents energy waste from temperature fluctuations and ensures optimal use of thermal energy
3Productivity
If solvent amount is increased to improve dissolution completeness, then recovery rate improves, but cost and environmental discharge increase
Solution Approach 1:
The patent implements a solvent recovery system that captures and reuses the solvent after the dissolution and separation process. This recovering action eliminates the need to discharge large amounts of solvent, reducing both cost and environmental impact while maintaining high recovery rates
Solution Approach 2:
The patent uses the solvent's own properties (solubility of polypropylene, volatility for separation) to achieve the separation process. The solvent serves itself by enabling dissolution and then being easily separated through evaporation, eliminating the need for additional large quantities of chemicals
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 achieves high plastic recovery rates with reduced solvent use and lower environmental costs, minimizing chemical waste discharge and promoting sustainable recycling practices.
Implementation Method 1
mixing the material containing plastics and a solvent to obtain a first mixture, wherein the plastic ingredient is soluble in the solvent; heating and stirring the first mixture at a temperature of 80° C. to 140° C. to dissolve the plastic ingredient in the solvent
Implementation Method 2
putting the dissolved liquid in a negative pressure environment to obtain the plastic ingredient
Implementation Method 3
putting the dissolved liquid in a negative pressure environment to obtain the plastic ingredient
Data Source
AI summary
The present invention provides a plastic recycling process, which firstly adopts a solvent along with a heating step to dissolve a recycle target, and then adopts a negative pressure environment to separate the solvent and the recycle target. The plastic recycling process of the present invention has a high plastic recovery rate, and the solvent is reusable and can be recycled, which not only reduces costs, but also avoids potential environmental problems.