Continuous Polymer Depolymerization Reactor for Inhomogeneous Waste
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Solution Overview
Problem
Current recycling processes for polymer waste are inefficient and costly due to the use of batch or semi-continuous methods, which lead to long residence times, unwanted by-products, and quality fluctuations, especially when dealing with inhomogeneous polymer mixtures, resulting in high costs and resource wastage.
Innovation Solution
A continuous process for depolymerizing inhomogeneous polymer mixtures using a reactor with multiple zones that separates polymer particles by size, allowing smaller particles to be depolymerized quickly and removed, while larger particles are held back until fully depolymerized, minimizing residence time and avoiding unnecessary exposure to high temperatures, thus preventing discoloration and by-product formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If batch processes are used for depolymerization, then all polymer particles can be processed, but the residence time is long leading to discoloration and by-product formation
Solution Approach 1:
The batch process is segmented into continuous zones within the reactor. The reactor is divided into multiple sections along the flow direction, each handling particles of different sizes. Small particles pass through quickly while large particles are retained longer, eliminating the need for long overall residence time while ensuring complete depolymerization of all particle sizes.
Solution Approach 2:
The system dynamically adjusts particle residence time based on particle size. Larger particles are automatically retained in the reactor longer through the particle size-dependent flow mechanism, while smaller particles move through faster. This dynamic adjustment ensures optimal processing time for each particle without manual intervention or extending the overall cycle time.
2Reliability
If batch processes are used for depolymerization, then complete processing is achieved, but quality fluctuations occur and storage capacities are required
Solution Approach 1:
The continuous process maintains constant operating conditions including temperature, pressure, and flow rates throughout operation. This continuity eliminates the start-stop cycles and varying conditions inherent in batch processes, ensuring consistent monomer quality and composition without fluctuations that would require storage and blending operations.
Solution Approach 2:
The system performs preliminary separation of particles by size before depolymerization begins. By pre-classifying particles into different size ranges and directing them to appropriate reactor zones, the system ensures that each particle type experiences optimal processing conditions from the start, preventing quality variations before they occur rather than correcting them afterward.
3Adaptability or versatility
If inhomogeneous polymer mixtures are processed, then all waste can be treated, but particle size variation requires extended processing time
Solution Approach 1:
Different regions of the reactor are assigned different functions based on local particle size requirements. The reactor contains zones optimized for small particles, medium particles, and large particles, with each zone having appropriate residence time and processing conditions. This local specialization allows the system to handle inhomogeneous mixtures efficiently without requiring extended time for the largest particles to dictate the overall process duration.
4Quantity of substance
If monomer solution is held under batch conditions, then complete depolymerization occurs, but discoloration and DEG content increase
Solution Approach 1:
The system rushes small particles through the reactor quickly since they depolymerize rapidly, preventing them from being exposed to prolonged high temperatures that cause discoloration and by-product formation. Meanwhile, large particles are selectively retained in zones where they receive the necessary processing time. This differential approach ensures complete depolymerization of all particles while minimizing harmful effects.
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 approach enables cost-effective, efficient depolymerization of polymer waste into high-quality monomers with reduced unwanted by-products, allowing for continuous operation and improved resource utilization without the need for pre-sorting by color, thereby enhancing the economic viability of recycling processes.
Implementation Method 1
a gradient is formed along the reactor, which is determined by the particle thickness and/or particle size
Implementation Method 2
the molecules are broken down in a batch process under high pressure using superheated steam and acid
Data Source
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AI summary
The present invention relates to a continuous method for treatment, in particular depolymerisation and/or dissolution of a polymer mixture, particularly a polymer mixture that is inhomogeneous in terms of particle size and/or particle thickness, forming a monomer liquid consisting substantially of a monomer, comprising the steps a) introducing the inhomogeneous polymer mixture into at least one vertical or horizontal reactor (3) having at least one reactor inlet and at least one reactor outlet, and/or b) mixing the inhomogeneous polymer mixture with at least one reactant or solvent; and c) introducing the inhomogeneous polymer mixture mixed with the reactant or solvent into at least one vertical or horizontal reactor (3) having at least one reactor inlet and at least one reactor outlet, and d) continuous depolymerisation and/or dissolution of the inhomogeneous polymer mixture to form the monomer liquid in the at least one vertical or horizontal reactor (3), wherein the particle size and/or particle thickness of the inhomogeneous polymer mixture is reduced continuously along the length of the reactor (3) from the reactor inlet to the reactor outlet, in particular by depolymerisation.