Horizontal Kneader Mixer for Thermal Polymer Separation
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Solution Overview
Problem
Existing thermal separation processes for thermoplastic polymers face limitations with high-molecular weight polymers, leading to fine particle formation, reduced degassing capacity, and high energy consumption, particularly due to temperature-related solidification and poor heat transfer in large-scale facilities.
Innovation Solution
Replacing the flash vessel with a horizontal kneader mixer that distributes the polymer-rich phase and applies mechanical kneading energy to maintain a high temperature, enhancing the separation efficiency and reducing residual volatile substances, while using a liquid stripping agent to adjust temperature and partial pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a flash vessel is used for thermal separation, then the polymer-rich phase can be separated from the solvent, but the polymer may solidify due to temperature decrease causing reduced degassing capacity and fine particle formation
Solution Approach 1:
The patent applies parameter changes by transitioning from a static flash vessel to a dynamic kneading device that actively controls temperature and pressure parameters. The kneading device maintains temperature above the polymer's melting point through mechanical heating, preventing solidification while achieving complete solvent removal, thus resolving the contradiction between separation capacity and degassing reliability
Solution Approach 2:
The patent replaces the purely thermal flash separation system with a mechanically active kneading system. The kneading device uses mechanical work to generate heat and maintain polymer in molten state, substituting the passive thermal field with an active mechanical field that provides both mixing and temperature control, thereby preventing solidification issues
2Productivity
If the polymer-rich phase is drawn from the flash container gravimetrically, then the separation can be completed, but high viscosity causes strong cavitation and limited transporting power
Solution Approach 1:
The patent replaces gravitational drainage with active mechanical pumping in a kneading device. The kneading mechanism provides positive displacement pumping action that can handle high-viscosity polymers without cavitation, maintaining complete separation while enabling reliable transport of the polymer-rich phase
3Manufacturing precision
If the polymer-rich bottom is supplied to a degassing extruder, then solvent and monomer residues can be removed, but temperature drop causes polymer solidification and pulverization into particles
Solution Approach 1:
The patent replaces the thermal field-based flash vessel with a mechanically active kneading device that maintains polymer in molten state through continuous mechanical heating. This mechanical field substitution prevents temperature drop and solidification during processing, enabling complete degassing while maintaining polymer compositional stability
Solution Approach 2:
The kneading device provides continuous mechanical action and heating throughout the processing cycle, maintaining the polymer in a stable molten state. This continuous useful action prevents the temperature fluctuations and solidification that occur in batch flash systems, ensuring consistent polymer composition and preventing pulverization
4Productivity
If large-scale facilities are used for thermal separation, then production capacity increases, but heat transfer becomes poor leading to energy consumption increases
Solution Approach 1:
The patent replaces inefficient thermal field-based heating with direct mechanical heating through the kneading action. The mechanical work done during kneading generates heat directly where it is needed, eliminating the poor heat transfer problems of large-scale thermal systems while maintaining high production capacity
Solution Approach 2:
The kneading device applies localized mechanical heating directly at the point of processing rather than relying on large-scale thermal fields. This local quality approach provides efficient heat generation exactly where the polymer needs heating, reducing overall energy consumption while maintaining productivity
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 increases the polymer-rich phase separation capacity, reduces energy consumption, and minimizes particle formation, enabling more effective degassing with reduced equipment size and lower residual volatile substances.
Implementation Method 1
the solvent is heated under pressure above the critical point of the solvent and then decompressed into a vessel such that a polymer-rich phase and a low-polymer phase form
Implementation Method 2
a polymer-rich phase and a low-polymer phase form
Implementation Method 3
In a static flash vessel, the resulting polymer-rich phase undergoes further flashing to pressures between 1 bar (gauge) and 10 bar (gauge)
Implementation Method 4
The heat of the separated, low-polymer phase is therefore usable for heating the educt
Implementation Method 5
the resulting polymer-rich solution is supplied—especially distributed over at least a portion of the length of a stirrer shaft—which is within the same vessel space and which heats the polymer composition by mechanical kneading energy
Data Source
AI summary
A process for thermal separation of a solution comprised of a thermoplastic polymer and a solvent involves heating a solvent under pressure above a critical point of the solvent; decompressing the heated solvent in a first vessel, such that a polymer-rich and a low-polymer phase form; and supplying the polymer-rich phase to a second vessel. In embodiments, on entry into the second vessel, a pressure jump occurs, the pressure jump leading to a thermal flash in the second vessel such that a polymer part of the polymer-rich phase rises to at least 70%, and a resulting polymer-rich solution is provided.