Method and system for polymer production
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Solution Overview
Problem
Existing methods struggle to produce polyolefin copolymers with high molecular weights in high concentrations while effectively reducing solvent levels, especially for elastomeric polymers with low bulk melting temperatures, and face challenges from stringent environmental regulations regarding volatile organic compound emissions.
Innovation Solution
A solution polymerization system utilizing a series of reactors, including continuous stirred tank reactors and loop reactors, combined with multiple devolatilization vessels and heat exchangers, to achieve high polymer concentrations and low solvent levels, using adiabatic flashing and sequential devolatilization to maintain the polymer in a single phase and reduce volatile content below 400 ppm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional solution polymerization is used to produce polyolefin copolymers, then polymer production capacity is achieved, but solvent levels remain high and polymer concentration is limited
Solution Approach 1:
The devolatilization process is divided into multiple sequential stages with progressively decreasing pressures. The first stage operates at higher pressure to remove bulk solvent, followed by second and third stages at progressively lower pressures to achieve ultra-low solvent levels (<400 ppm). This segmented approach enables efficient solvent removal while maintaining high polymer concentration throughout the process.
Solution Approach 2:
The system dynamically changes operating parameters, specifically pressure and temperature, across different devolatilization stages. Pressure is reduced sequentially from stage one to stage three, while temperature is adjusted to optimize solvent vaporization. These parameter changes enable the system to achieve both high polymer concentration and ultra-low solvent content.
2Use of energy by moving object
If adiabatic flashing is used to reduce solvent levels, then energy consumption is reduced, but temperature control becomes challenging
Solution Approach 1:
The system incorporates temperature monitoring and control mechanisms in each devolatilization stage to manage the temperature drops caused by adiabatic flashing. By providing feedback on actual temperature conditions, the system can adjust operating parameters to maintain optimal conditions for solvent removal while preventing excessive cooling that would affect polymer quality.
Solution Approach 2:
The polymer solution is preheated before entering each devolatilization stage to compensate for the temperature drop that will occur during adiabatic flashing. This preliminary heating action ensures that the polymer maintains appropriate temperature and viscosity characteristics throughout the solvent removal process, enabling efficient operation without excessive energy input.
3Manufacturing precision
If multiple devolatilization stages are implemented to achieve low solvent levels, then polymer purity is improved, but system complexity increases
Solution Approach 1:
Multiple devolatilization stages are combined into a single integrated system with shared infrastructure. Common elements such as heat exchangers, pressure control systems, and polymer transfer mechanisms are consolidated across all three stages, reducing overall system complexity while maintaining the purity benefits of multi-stage processing.
Solution Approach 2:
Each devolatilization stage is designed with multi-functional capabilities, serving both as a solvent removal unit and as a polymer concentration unit. The system simultaneously achieves multiple objectives - solvent elimination, polymer concentration, and temperature management - within each stage, reducing the need for separate dedicated equipment and simplifying the overall process design.
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 system efficiently produces polyolefin copolymers with high molecular weights and low solvent content, meeting product quality and environmental regulation standards by maintaining the polymer in a single phase and effectively removing volatile components.
Implementation Method 1
using adiabatic flashing and sequential devolatilization to maintain the polymer in a single phase and reduce volatile content below 400 ppm
Implementation Method 2
A solution polymerization system utilizing a series of reactors, including continuous stirred tank reactors and loop reactors, combined with multiple devolatilization vessels and heat exchangers
Implementation Method 3
using adiabatic flashing and sequential devolatilization to maintain the polymer in a single phase
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Disclosed herein is a system for solution polymerization comprising a reactor system that is operative to receive a monomer and to react the monomer to form a polymer; a plurality of devolatilization vessels located downstream of the reactor system, where each devolatilization vessel operates at a lower pressure than the preceding devolatilization vessel; and a heat exchanger disposed between two devolatilization vessels and in fluid communication with them, where the heat exchanger has an inlet port temperature of 100°C to 230°C, an outlet port temperature of 200°C to 300°C, an inlet port pressure of 35 to 250 kgf/cm2 and an outlet port pressure of 20 to 200 kgf/cm2; and wherein the polymer solution remains in a single phase during its residence in the heat exchanger.