Twin-Screw Resin Decomposition with Cooling to Suppress Backflow
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing resin decomposition methods using subcritical or supercritical fluids require expensive, dedicated apparatus due to high temperature and pressure conditions, leading to high processing costs and potential backflow issues in open-ended extruders.
Innovation Solution
A decomposition method and apparatus using a twin-screw extruder with a cooling mechanism to maintain subcritical or supercritical conditions within a cylinder, suppressing backflow by cooling the cylinder between the resin and fluid suppliers, and employing a safety hopper to manage resin flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a sealed apparatus is used for subcritical or supercritical fluid decomposition, then decomposition efficiency is improved, but equipment cost and complexity increase significantly
Solution Approach 1:
The patent applies a standard open-ended extruder that can serve dual purposes: traditional resin extrusion and subcritical/supercritical fluid decomposition. By utilizing the existing extruder structure for both functions, the system avoids the need for dedicated sealed decomposition apparatus, thereby reducing equipment complexity and cost while maintaining decomposition efficiency
Solution Approach 2:
The patent changes the operational parameters of the extruder by controlling the barrel temperature to maintain subcritical or supercritical fluid states within the extruder. This parameter control allows the standard extruder to achieve decomposition functionality without requiring specialized sealed structure, resolving the contradiction between decomposition efficiency and equipment complexity
2Productivity
If high temperature and pressure conditions are used for decomposition, then decomposition rate is improved, but backflow of resin occurs in open-ended extruders
Solution Approach 1:
The patent applies preliminary cooling to the barrel section between the resin supply and fluid supply ports before introducing the subcritical/supercritical fluid. This pre-cooling creates a temperature gradient that prevents resin backflow by maintaining lower pressure in the cooled section, thereby preventing the backflow problem before it occurs while still allowing high temperature decomposition in the downstream section
Solution Approach 2:
The patent creates different temperature zones within the extruder barrel: a cooler zone at the upstream section (near resin supply) to prevent backflow, and a high-temperature zone at the downstream section (near fluid supply and decomposition zone) to achieve high decomposition rate. This local quality differentiation resolves the contradiction between decomposition rate and backflow control
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
Efficient resin decomposition is achieved with reduced equipment costs and minimized backflow, enabling continuous and safe operation while producing reusable monomers.
Implementation Method 1
the cylinder is cooled between the resin supplier and the fluid supplier by a coolant
Implementation Method 2
a step (b) of heating and pressurizing and then melt-plasticizing the supplied thermoplastic resin in the cylinder
Implementation Method 3
a step (d) of decomposing the melt-plasticized thermoplastic resin by exposing the melt-plasticized thermoplastic resin to a subcritical state or a supercritical state by the supplied fluid
Data Source
AI summary
A decomposition method and a decomposition apparatus for resin capable of safely and efficiently decomposing a resin are provided. A decomposition apparatus for resin 10 includes: a cylinder 12; a resin supplier 11 supplying a thermoplastic resin to the cylinder 12; a screw 12a transporting the supplied thermoplastic resin and a melt-plasticized thermoplastic resin; a fluid supplier 13 supplying a heated and pressurized fluid into the cylinder in order to decompose the melt-plasticized thermoplastic resin in a subcritical state or a supercritical state; an extruder 14 provided at a tip of the cylinder 12 and discharging a decomposed product of the thermoplastic resin to outside of the cylinder; a rotary drive mechanism 15 rotationally driving the screw 12a; and a cooling mechanism 16 being capable of cooling the cylinder 12.