Static Devolatilisation Apparatus with Multi-Stage Distributor
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Solution Overview
Problem
Static devolatilization apparatuses for viscous liquids, such as polymers, face inefficiencies due to limited specific surface creation and short residence time under vacuum or reduced pressure, leading to insufficient removal of volatile components and potential polymer degradation.
Innovation Solution
A static devolatilization apparatus with a distributor sub-unit having a second discharge region that increases the residence time and specific surface of the devolatilized liquid, allowing for a second devolatilization step on its surface, enhancing mass transfer kinetics without the need for moving parts or excessive thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a static devolatilisation apparatus is used with conventional configuration, then the equipment complexity is reduced and energy consumption is lowered, but the residence time under vacuum is insufficient and specific surface creation is limited, leading to inadequate volatile component removal
Solution Approach 1:
The devolatilisation apparatus is segmented into multiple functional regions: a first devolatilisation region with a distributor plate for initial volatile removal, and a second devolatilisation region with a second distributor plate for enhanced volatile component removal. This segmentation allows each region to perform a specific devolatilisation function, increasing overall efficiency without requiring complex moving parts or high energy input.
Solution Approach 2:
The invention introduces a vertical dimension to devolatilisation by stacking distributor plates at different heights within the apparatus. The first distributor plate is positioned at a first height and the second distributor plate at a second height, creating multiple devolatilisation zones along the vertical axis. This dimensional arrangement increases the effective residence time and specific surface area for mass transfer without expanding the horizontal footprint or adding mechanical complexity.
2Productivity
If the residence time under vacuum is increased to improve devolatilisation efficiency, then volatile component removal is enhanced, but polymer degradation increases due to prolonged exposure to harsh conditions
Solution Approach 1:
The devolatilisation process is segmented into multiple stages occurring at different vertical levels. The first devolatilisation region removes the bulk of volatile components through a distributor plate, while the second devolatilisation region with its second distributor plate provides additional volatile removal capacity. This staged approach achieves high devolatilisation efficiency without requiring excessively long residence times that would cause polymer degradation.
Solution Approach 2:
The first distributor plate performs preliminary devolatilisation by creating a first devolatilised liquid stream with reduced volatile content before this stream reaches the second distributor plate. This preliminary action reduces the volatile load on subsequent processing stages, enabling efficient final devolatilisation with minimal exposure to harsh vacuum conditions, thereby preventing polymer degradation.
3Productivity
If a stripping agent is used to enhance foaming and degassing efficiency, then volatile component removal is improved, but chemical incompatibility may cause polymer degradation or the overhead system capacity becomes insufficient
Solution Approach 1:
The apparatus segments the devolatilisation function across multiple distributor plates positioned at different heights. Each distributor plate creates foam and facilitates volatile removal through its discharge openings. This distributed foaming mechanism enhances degassing efficiency without requiring chemical stripping agents, thereby avoiding polymer degradation from chemical incompatibility while remaining within overhead system capacity.
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 configuration significantly increases the efficiency of volatile component removal, reducing residual volatile content by over 80% while minimizing polymer degradation, achieving higher product quality with reduced equipment complexity and energy consumption.
Implementation Method 1
enhancing mass transfer kinetics
Implementation Method 2
The driving force for the devolatilisation is the lower chemical potential in the gas phase than in the polymer. This difference of chemical potential causes the formation of a concentration gradient at the polymer interface resulting in a diffusion flux from the polymer to the gas phase.
Implementation Method 3
a phase separation chamber in said upper region of said container, wherein the phase separation chamber comprises an inlet for the viscous liquid to be treated
Data Source
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AI summary
A static devolatilisation apparatus (1) adapted for devolatilising a viscous liquid (2) comprising a volatile component is disclosed. The apparatus (1) comprises a phase separation chamber (100) in an upper region (5) for treating the viscous liquid (2) in a first devolatilisation step to form a first devolatilised viscous liquid (21), and a distributor sub-unit 200 is located below the phase separation chamber (100) and above a lower sump region (4). The sub-unit (200) has a second discharge region (222) embodied such that it is contacted by the first devolatilised viscous liquid (21), and the region (222) has a surface (223) embodied such that the first devolatilised viscous liquid (21) is treated in a second devolatilisation step. The present invention further relates to a process to devolatilising a viscous liquid using the apparatus (1) and also to the use of the apparatus (1) in the devolatilisation of polymer melt or solution.