Polymer Solution Concentrator with Counter-Rotating Screws
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Solution Overview
Problem
Conventional devolatilization processes for polymer formulations face limitations in achieving high concentrations and viscosities due to viscosity issues, metering difficulties, and high energy consumption, leading to inefficient solvent removal and equipment size constraints.
Innovation Solution
A polymer solution concentrator machine with a conically-shaped barrel and counter-rotating intermeshing screws, featuring vapor removal and positive displacement geometries, allows for efficient concentration of polymer solutions from 40 weight percent to 98 weight percent, reducing energy and resource requirements while overcoming viscosity and metering challenges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If steam stripping is employed to remove solvent from polymer formulation, then solvent removal is achieved, but energy consumption increases significantly
Solution Approach 1:
The patent employs flash evaporation, a phase transition process, where the polymer formulation is rapidly depressurized causing the solvent to transition from liquid to vapor phase. This eliminates the need for steam heating while achieving effective solvent removal through pressure-driven phase change rather than heat-driven phase change.
Solution Approach 2:
The patent extracts the solvent from the polymer formulation through flash evaporation in a flash tank, separating the vapor phase (solvent) from the liquid phase (concentrated polymer). This extraction approach achieves solvent removal without requiring the steam stripping process, thereby reducing energy consumption.
2Quantity of substance
If flash tank is used for direct devolatilization, then solvent removal is achieved, but equipment size becomes large
Solution Approach 1:
The patent combines the flash evaporation tank and the extruder into a single integrated unit where the flash tank is positioned above the extruder and the concentrated polymer formulation flows directly from the flash tank into the extruder. This merging of functions reduces the overall equipment footprint while maintaining effective solvent removal capability.
Solution Approach 2:
The patent implements a nested configuration where the flash tank is vertically integrated with the extruder, and the vapor takeoff system is nested within the overall device structure. This nesting approach minimizes the external dimensions of the equipment while preserving the internal functional volumes needed for effective devolatilization.
3Quantity of substance
If polymer formulation is concentrated to high viscosity, then solvent removal efficiency improves, but metering difficulties increase
Solution Approach 1:
The patent replaces traditional mechanical metering systems with a gravity-fed delivery mechanism. The flash tank is positioned above the extruder, allowing the concentrated polymer formulation to flow into the extruder under gravity control. This substitution eliminates metering difficulties associated with high-viscosity materials while maintaining effective concentration.
Solution Approach 2:
The patent uses gravity flow by positioning the flash tank at a higher elevation than the extruder, creating a gravitational potential difference that drives the flow of concentrated polymer formulation. This equipotential approach ensures consistent material delivery without requiring complex metering mechanisms, even for highly viscous materials.
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 solution enables efficient concentration of polymer solutions to higher viscosities, reduces energy consumption, and minimizes equipment size, addressing the limitations of conventional methods by achieving higher concentrations with lower solvent residual levels and improved processing efficiency.
Implementation Method 1
The pre-heater elevates the formulation temperature, increasing the vapor pressure of the solvents
Implementation Method 2
The reduction in pressure from the super-heated solution to the lower flash tank pressure causes the solvent to vaporize and separate from the polymer solution
Implementation Method 3
causes the solvent to vaporize and separate from the polymer solution
Implementation Method 4
A pair of conically-shaped, counter-rotating intermeshing screws is disposed in the barrel, and the screws include a portion with a vapor removal geometry and a portion with a positive displacement geometry
Data Source
AI summary
An improved polymer solution concentrator and accompanying devolatilization process enable concentration of polymer solutions to higher concentrations and viscosities than prior art equipment, overcome the viscosity limits and metering difficulties of the prior art, reduce the overall size of the devolatilization system, and reduce the energy, resources and cost required to finish polymer formulations. The concentrator replaces a conventional flash tank and includes a generally solid conically-shaped twin barrel. A pair of counter-rotating intermeshing screws is disposed in the barrel, and includes a portion with a vapor removal geometry and a portion with a positive displacement geometry. A vapor discharge port is formed in the barrel, and upon rotation of the screws in the barrel, a polymer formulation is concentrated from a value below about 40 weight percent to a value of up to about 98 weight percent.