Concentric Injection Nozzle for Polyolefin Morphology Control
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Solution Overview
Problem
In gas phase polymerization processes, controlling the product morphology of polyolefins is challenging due to issues with particle size distribution, where excessive small particles (fines) can cause reactor shutdowns and larger particles lead to entrainment and plugging, disrupting downstream handling.
Innovation Solution
Controlling the feed temperature and flow rate through a concentric flow path nozzle into a fluidized bed reactor, allowing for precise adjustment of polymer morphology by varying the temperature and flow rate to alter the percentage of fines produced, thereby optimizing particle size distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If feed temperature and flow rate are not controlled, then polymer morphology cannot be controlled, but controlling these parameters increases process complexity
Solution Approach 1:
The patent applies parameter changes by systematically varying feed temperature and flow rate to control polymer morphology. Different temperature and flow rate combinations produce different particle size distributions, allowing precise control of fines content and overall polymer morphology through parameter optimization rather than complex mechanical modifications.
Solution Approach 2:
The patent replaces complex mechanical control systems with thermal and flow-based control mechanisms. Instead of using complex mechanical devices to control particle morphology, the invention uses feed temperature and flow rate parameters to achieve the same effect, substituting mechanical complexity with controllable process parameters.
2Productivity
If feed temperature is increased, then polymerization rate increases, but percentage of fines increases by at least 1%
Solution Approach 1:
The patent uses parameter changes to balance productivity and fines production. By optimizing the combination of feed temperature and flow rate, the process achieves high polymerization rates while maintaining acceptable fines levels through precise parameter control rather than sacrificing productivity.
Solution Approach 2:
The patent applies dynamics by making the feed temperature and flow rate adjustable and optimizable based on desired outcomes. The system allows dynamic adjustment of parameters to achieve the optimal balance between production rate and particle quality, adapting conditions to specific operational requirements.
3Productivity
If feed flow rate is increased, then production rate increases, but particle size distribution deteriorates with higher fines content
Solution Approach 1:
The patent applies parameter changes by coordinating adjustments of both feed flow rate and feed temperature. The optimal particle size distribution is achieved through a specific combination of flow rate and temperature parameters, where changes in one parameter are compensated by adjustments in the other to maintain desired product quality at high production rates.
4Quantity of substance
If fines content is high, then small particles are produced, but reactor shutdowns occur due to heat exchanger buildup
Solution Approach 1:
The patent uses parameter changes to control fines content at levels that prevent heat exchanger buildup. By optimizing feed temperature and flow rate, the process produces polymer with sufficient quantity while maintaining particle morphology that does not lead to operational disruptions, ensuring continuous reliable reactor operation.
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 method effectively reduces the percentage of fines produced, preventing reactor shutdowns and plugging issues, while maintaining acceptable levels of desirably sized particles, thus improving process efficiency and handling of polyolefin products.
Implementation Method 1
flowing a catalyst through a first concentric flow path of the injection nozzle having two or more concentric flow paths and into a fluidized bed disposed within a reactor; flowing a first amount of feed comprising one or more olefins, one or more inert fluids, or a combination thereof through a second concentric flow path of the injection nozzle
Implementation Method 2
A gas phase fluidized bed reactor can include a reaction zone and a so-called velocity reduction zone. The reaction zone can include a bed of growing polymer particles, formed polymer particles, and a minor amount of catalyst particles fluidized by the continuous flow of gaseous monomer and diluent
Implementation Method 3
This cycle gas stream can be passed through a heat exchanger, where at least a portion of the heat of polymerization can be removed
Implementation Method 4
and then compressed in a compressor and returned to the reaction zone
Implementation Method 5
contacting the first amount of feed with the catalyst within the fluidized bed at conditions sufficient to produce a polyolefin having a first size distribution
Data Source
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AI summary
Methods and systems for olefin polymerization are provided. The method for olefin polymerization can include flowing a catalyst through an injection nozzle and into a fluidized bed disposed within a reactor. The method can also include flowing a feed comprising one or more monomers, one or more inert fluids, or a combination thereof through the injection nozzle and into the fluidized bed. The feed can be at a temperature greater than ambient temperature. The method can also include contacting one or more olefins with the catalyst within the fluidized bed at conditions sufficient to produce a polyolefin.