Conjugated Diene Polymerization Reactor System with Heat Reflux
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Solution Overview
Problem
The existing methods for preparing conjugated diene-based polymers face challenges in improving productivity while preventing gel production in polymerization reactors, leading to issues with uniform reaction states and increased energy requirements for solvent and monomer removal.
Innovation Solution
A method involving parallel and series polymerization reactors, where the first polymer solution is processed in parallel reactors and then transferred to series reactors with a condenser to reflux gas and maintain a lower reaction temperature, reducing polymer concentration in the first reactor and increasing it in the final reactor, thereby preventing gel formation and optimizing energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ratio of monomer to solvent is increased to improve productivity, then productivity is improved, but polymer solubility in solvent decreases causing non-uniform reaction state and broad molecular weight distribution
Solution Approach 1:
The patent divides the polymerization process into multiple stages using a multi-stage polymerization reactor system. The first stage uses a higher monomer-to-solvent ratio for rapid polymerization, while subsequent stages use progressively lower ratios to maintain solubility and reaction uniformity. This segmentation allows each stage to operate under optimal conditions without compromising overall process stability.
Solution Approach 2:
The patent introduces a pre-polymerization stage before the main polymerization process. In this preliminary stage, a small amount of polymer is formed under controlled conditions, which then serves as a seed for the subsequent polymerization stages. This preliminary action ensures that the polymerization proceeds uniformly through predetermined stages, preventing non-uniform reaction states.
2Productivity
If the ratio of polymer in the polymerization reactor is increased to improve productivity, then productivity is improved, but gel formation is accelerated requiring reactor shutdown and washing
Solution Approach 1:
The patent segments the polymerization process into multiple reactors or stages, each operating at different polymer concentrations. The first reactor operates at high polymer concentration for rapid production, while subsequent reactors operate at lower concentrations to prevent gel formation. This segmentation allows continuous operation without shutdown for washing.
Solution Approach 2:
The patent introduces an intermediate stage or reactor that receives polymer solution from the first reactor and processes it under conditions that prevent gel formation. This intermediary system acts as a buffer, allowing the first reactor to operate at high productivity while the intermediate stage manages the polymer concentration to prevent gelation and ensure continuous operation.
3Use of energy by moving object
If polymer concentration is increased in the polymerization reactor to reduce solvent removal energy, then energy consumption for solvent removal is reduced, but gel formation is promoted decreasing productivity
Solution Approach 1:
The patent divides the polymerization into stages with increasing polymer concentration. Early stages operate at lower concentrations to prevent gel formation and maintain productivity, while later stages operate at higher concentrations to minimize the energy required for solvent removal. This segmented approach optimizes both productivity and energy efficiency.
Solution Approach 2:
The patent systematically changes the polymer concentration parameter through different reaction stages. The concentration increases progressively from the first reactor to subsequent reactors, allowing the process to transition from productivity-focused operation to energy-efficiency-focused operation. This parameter change strategy prevents gel formation in early stages while maximizing energy efficiency in later stages.
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 approach allows for the preparation of high-concentration conjugated diene-based polymers with reduced energy consumption and minimized gel production in the first reactor, enhancing productivity and maintaining uniform polymer concentration.
Implementation Method 1
gas produced by polymerization heat is condensed by a condenser provided in the series polymerization reactor and refluxed to the parallel polymerization reactors
Implementation Method 2
a reaction temperature of the series polymerization reactor is maintained to be lower than a reaction temperature of the parallel polymerization reactors by 10° C. or more
Data Source
AI summary
A method of preparing a conjugated diene-based polymer is provided. The method includes: adding a conjugated diene-based monomer, a catalyst, and a solvent to parallel polymerization reactors, performing a polymerization reaction to prepare a first polymer solution including a first conjugated diene-based polymer; and adding the first polymer solution to a polymerization reactor connected in series to the parallel polymerization reactors, performing the polymerization reaction to prepare a second polymer solution including a second conjugated diene-based polymer. After the polymerization reaction in the series polymerization reactor, gas produced by polymerization heat is condensed in the series polymerization reactor and refluxed to the parallel polymerization reactors, and a reaction temperature of the series polymerization reactor is maintained to be lower than a reaction temperature of the parallel polymerization reactors by 10° C. or more.