Loop Reactor Dual Outlet Segmentation for Polymer Concentration Control
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Solution Overview
Problem
The existing olefin polymerization processes in loop reactors face challenges in adjusting polymer concentration during start-up and maintaining consistent residence time, leading to inefficiencies and reduced catalyst productivity.
Innovation Solution
Incorporating two outlets in the loop reactor, one located at the outer periphery and the other at the inner periphery, allows for the withdrawal of polymer slurries with concentrations equal to or higher than, and lower than, the average reactor concentration, respectively, enabling precise control of polymer concentration and residence time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the outlet is located to withdraw slurry with higher polymer concentration than average, then the polymer concentration in withdrawn slurry is improved, but the residence time of olefin polymer in the loop reactor decreases
Solution Approach 1:
The outlet is divided into two separate outlets: a first outlet positioned to withdraw slurry with higher polymer concentration and a second outlet positioned to withdraw slurry with lower polymer concentration. This segmentation allows independent control of each outlet's withdrawal characteristics, enabling simultaneous optimization of polymer concentration and residence time by adjusting the relative opening degrees of the two outlets.
2Quantity of substance
If the outlet is located to withdraw slurry with higher polymer concentration than average, then the polymer concentration in withdrawn slurry is improved, but the catalyst productivity decreases
Solution Approach 1:
By segmenting the outlet into two separate outlets with different withdrawal characteristics, the system can independently optimize polymer concentration withdrawal while maintaining adequate residence time for catalyst productivity. The first outlet provides high-concentration slurry for efficient polymer recovery, while the second outlet ensures sufficient residence time, thereby resolving the contradiction between polymer concentration and catalyst productivity.
3Device complexity
If a single outlet configuration is used, then the device complexity is reduced, but the control precision of polymer concentration and residence time decreases
Solution Approach 1:
The outlet is segmented into two independently controllable outlets, each with specific positioning characteristics. This segmentation provides precise control over polymer concentration and residence time by adjusting the relative opening degrees of the two outlets, while the overall device complexity remains manageable through straightforward implementation of dual outlet structures with independent control mechanisms.
Data Source
AI summary
Method for preparing olefin polymer in a loop reactor, said loop reactor comprises a first outlet for withdrawing polymer slurry from the loop reactor, and a second outlet for withdrawing a polymer slurry from the loop reactor, wherein the first outlet is located such that polymer slurry is withdrawn having a concentration of polymer which is equal or higher than the average concentration of polymer in the loop reactor, and the second outlet is located such that polymer slurry is withdrawn having a concentration of polymer which is lower than the average concentration of polymer in the loop reactor, the method comprises the steps of supplying olefin monomers and a catalytic system to the loop reactor to form a polymer slurry in the loop reactor, and controlling the total amount of polymer and/or the total amount of polymer slurry withdrawn from the loop reactor by adjusting the ratio of polymer slurry withdrawn through the first outlet and polymer slurry withdrawn through the second outlet.