Polymer Vapor Screening Assembly for Low-Entrainment Separation
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Solution Overview
Problem
In solution polymerization processes, the rapid pressure drop during vapor stream separation leads to significant polymer entrainment, causing fouling in subsequent equipment and reducing separation efficiency, which can impact temperature control and production capacity.
Innovation Solution
A screening assembly is introduced that combines a separation step with a screening step, where the vapor phase is contacted with a condensed vapor phase in a countercurrent flow, utilizing liquid and gas distributors to enhance the removal of entrained polymer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a rapid pressure drop is used during vapor-liquid separation to increase separation speed, then separation efficiency is improved, but polymer entrainment in vapor streams increases
Solution Approach 1:
A screening device is introduced as an intermediary component between the flash separator and subsequent equipment. This device uses a screening medium (such as a mesh or filter) to physically intercept and retain polymer particles that are entrained in the vapor stream, allowing the vapor to pass through while blocking the harmful polymer particles. This resolves the contradiction by maintaining the rapid pressure drop for efficient separation while adding a intermediate step to remove polymer entrainment.
Solution Approach 2:
The separation process is divided into multiple stages: first, rapid pressure drop separation in a flash separator to achieve high separation speed; second, a screening stage to remove polymer entrainment; and optionally third, condensation stages. This segmentation allows each stage to optimize for its specific function - speed in the first stage, purification in the second stage - thereby resolving the contradiction between separation speed and polymer entrainment.
2Loss of substance
If multi-step evaporation processes are used to reduce volatile levels in polymer, then volatile removal is improved, but equipment complexity and fouling risk increase
Solution Approach 1:
The harmful polymer entrainment is extracted and removed from the vapor stream at an early stage using the screening device, before the vapor proceeds to condensation and recovery sections. This prevents polymer from reaching and fouling subsequent equipment. By removing the problematic component early, the system achieves effective volatile removal through simplified single-step or reduced multi-step evaporation processes without suffering from the complexity and fouling risks associated with extended multi-step processes.
3Use of energy by moving object
If vapor streams are reused as reactor feed to improve process efficiency, then energy efficiency is improved, but fouling of reactor feed equipment increases
Solution Approach 1:
The screening device performs a preliminary cleaning action on the vapor stream, removing polymer particles before the vapor is condensed and reused as reactor feed. This preliminary removal of harmful particles prevents fouling of reactor feed equipment and injection systems downstream. By taking this preventive action early in the process, the system can confidently reuse vapor streams for energy efficiency without suffering from fouling problems in the reactor feed path.
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 effectively reduces polymer entrainment, preventing fouling and enhancing separation efficiency by adhering polymer particles to the condensed phase, thereby improving heat removal and process stability.
Implementation Method 1
polymer entrainment occurs at high levels. This might be the case, as the amount of evaporating material is largest in the first separation step
Implementation Method 2
the rapid pressure drop during vapor-liquid separation leads to high levels of polymer entrainment in vapor streams
Implementation Method 3
a first inlet connected to the conduit for the polymer-lean vapor stream, a first outlet for withdrawing a cleaned vapor stream
Data Source
Figure 1a~1b
Figure 2a~2d
Figure 3
AI summary
The present invention is concerned with a screening assembly comprising a separating device connected to a conduit for an effluent stream comprising a polymer and a mixture of hydrocarbons, wherein the separating device is configured to separate the effluent stream into a polymer-rich stream and a polymer-lean vapor stream, wherein the first separation device comprises an inlet, a first outlet for withdrawing a polymer-rich stream, and a second outlet for withdrawing a polymer-lean vapor stream, a screening device connected to the separating device via a conduit for the polymer-lean vapor stream, wherein the screening device comprises a first inlet connected to the conduit for the polymer-lean vapor stream, a first outlet for withdrawing a cleaned vapor stream, a second outlet for withdrawing a polymer-comprising condensed vapor stream, and at least one second inlet for introducing a condensed vapor stream.