Continuous Plastic Depolymerization Flow to Prevent Clogging
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Solution Overview
Problem
Conventional batch processes for depolymerizing and dissolving plastic are energy-intensive and require significant equipment and time, as they involve frequent heating, cooling, and refilling of reaction vessels, which wastes energy and complicates the simulation of continuous flow.
Innovation Solution
A continuous flow-through process where a mixture of solid plastic particles in a solvent is continuously pumped through a heating chamber at a controlled speed to maintain suspension and heat the mixture to a reaction temperature, converting it into a homogeneous solution, using a system with a pump, preheating, heating zones, and cooling zones to optimize energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If batch processes are used for depolymerizing plastic, then depolymerization can be completed, but energy consumption increases and equipment complexity increases
Solution Approach 1:
The patent implements a continuous flow-through process where plastic particles are continuously fed into a reaction tube, depolymerized at elevated temperatures, and collected as molten product. This eliminates the batch process cycle of heating, cooling, and refilling reaction vessels, maintaining continuous operation to reduce energy waste and simplify equipment requirements
Solution Approach 2:
The patent extracts the depolymerization reaction from traditional batch reaction vessels with heating jackets and agitators, transferring it to a continuous flow system using a reaction tube. This removes the need for complex heating/cooling cycles and vessel refilling operations, directly addressing the energy and equipment complexity issues
2Use of energy by moving object
If batch processes are used for dissolving plastic, then dissolution can be completed, but energy consumption increases
Solution Approach 1:
The patent implements continuous dissolution where plastic particles are continuously fed through a reaction tube with solvent, dissolved at elevated temperatures, and collected as a homogeneous solution. This eliminates the batch cycle of heating, dissolving, cooling, and transferring, reducing both energy consumption and total process time
Solution Approach 2:
The patent changes the temperature parameter continuously along the reaction tube, heating the plastic-solvent mixture to dissolution temperature and maintaining it for the required residence time. This continuous temperature control enables efficient dissolution without the energy-intensive heating and cooling cycles of batch processes
3Productivity
If plastic particles are flowed through heating chamber, then continuous depolymerization is achieved, but particle agglomeration and line clogging may occur
Solution Approach 1:
The patent introduces a dispersant into the plastic particle suspension before feeding it into the reaction tube. This preliminary action prevents particle agglomeration and clogging by maintaining particle separation, ensuring reliable continuous flow through the heating chamber without interruptions
Solution Approach 2:
The patent uses a dispersant as an intermediary substance that mediates between plastic particles and the solvent. The dispersant adsorbs onto particle surfaces, providing steric or electrostatic repulsion that prevents agglomeration and maintains stable suspension flow through the reaction system
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 significantly reduces energy consumption, achieving non-renewable energy usage of less than 5 MJ/kg of plastic, and allows for continuous conversion of plastic into a liquefied reaction product without clogging, enhancing efficiency and reducing equipment needs.
Implementation Method 1
transferring heat through the line in the heating chamber to heat the mixture to a reaction temperature
Implementation Method 2
continuously flowing a mixture containing solid plastic particles in a solvent through a line in a heating chamber at a particle speed sufficient to maintain suspension
Implementation Method 3
raising the temperature of the heterogeneous mixture flowing through the line to a reaction temperature of at least 150° C. The conversion of the heterogeneous mixture containing the solid plastic particles into a homogeneous solution containing a liquefied reaction product is started in the heating zone
Data Source
AI summary
A continuous flow process and system for depolymerizing plastic. A heterogeneous mixture of solid plastic particles, a solvent, and a catalyst are pumped continuously through a heating zone at a flow rate resulting in a particle speed sufficient to keep the plastic particles in suspension. The heterogeneous mixture is heated in the heating zone and maintained in a hold zone to complete depolymerization of the mixture into a homogeneous solution containing a liquefied reaction product. The homogeneous solution is cooled to solidify and precipitate a solid reaction product. The solid reaction product is separated from the solvent to be recycled. Contaminants are removed from the solvent, and the solvent is recirculated for use as a constituent of the heterogeneous mixture.