Bimodal Slurry Polymerization with Flash Dehydrogenation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing bimodal polymers through post-reactor blending or series reactor operation face challenges such as increased costs and inconsistent product quality due to hydrogen purging requirements, which slow down production.
Innovation Solution
A process involving a first loop reactor followed by a high pressure flash tank, re-slurry mixer, and second loop reactor, where hydrogen concentration is reduced through vaporization and dilution, allowing for continuous production of low and high molecular weight polymers with reduced hydrogen content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If post-reactor blending is used to form bimodal polymer blend, then product performance is improved, but production cost increases and productivity decreases
Solution Approach 1:
The patent combines two separate polymerization reactions into a single reactor system, producing both low molecular weight homopolymer and high molecular weight copolymer simultaneously within the same reactor. This eliminates the need for separate post-reactor blending operations, thereby improving productivity while maintaining product performance through in-reactor bimodal polymer formation.
Solution Approach 2:
The patent performs preliminary polymerization of both polymer types within the reactor before any blending or mixing operations are needed. By pre-forming the bimodal polymer mixture in-reactor, the system eliminates subsequent blending steps that would otherwise be required to achieve the desired polymer blend, thus accelerating production.
2Manufacturing precision
If series reactor operation is used to produce bimodal polymers, then product consistency is improved, but hydrogen purging requirements slow down production
Solution Approach 1:
The patent merges the functions of multiple series reactors into a single reactor system that can simultaneously produce both low and high molecular weight polymers. This consolidation eliminates the intermediate transfer and purging steps between reactors that slow down production, while maintaining product consistency through controlled in-reactor polymerization conditions.
Solution Approach 2:
The patent extracts the hydrogen purging requirement from the process by designing a single-reactor system where both polymers are formed simultaneously. This eliminates the need to purge hydrogen between reactor stages, as there are no intermediate transfers requiring purging, thereby accelerating production while maintaining product consistency.
3Quantity of substance
If hydrogen is purged from polymer mixture before second reactor, then hydrogen concentration is reduced, but production time increases
Solution Approach 1:
The patent takes out the hydrogen purging step entirely from the process by using a single-reactor configuration. Since both low and high molecular weight polymers are produced simultaneously in one reactor, there is no intermediate polymer mixture transfer requiring hydrogen removal, thus eliminating time loss while still achieving the necessary hydrogen concentration control for copolymer formation.
Solution Approach 2:
The patent performs preliminary control of hydrogen concentration within the single reactor during the polymerization process itself, rather than requiring post-polymerization purging. By managing hydrogen levels in-reactor during simultaneous polymer formation, the system achieves the required hydrogen concentration without the time-consuming separate purging 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 enables high throughput and cost-effective production of bimodal polymers with improved homogeneity and reduced hydrogen content, enhancing productivity and product consistency.
Implementation Method 1
separating the first polymerization effluent in the high pressure flash tank to vaporize from about 50% to about 100% of the first diluent and unreacted monomer
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
Processes and apparatus for preparing bimodal polymers are provided. In some embodiments, processes include introducing a monomer, a first diluent, a catalyst, hydrogen, at a first hydrogen concentration, and optional comonomer, to a first loop reactor to produce, under polymerization conditions, a first slurry of polymer solids. Processes may also include continuously discharging the first slurry of polymer solids from the loop reactor as a first polymerization effluent to a first flash tank; separating the first polymerization effluent in the first flash tank to provide a first concentrated polymer slurry with significantly lower hydrogen concentration; and transferring the first concentrated polymer slurry from the flash tank to a re-slurry mixer. Processes may further include introducing a re-slurry mixer diluent to the first concentrated polymer slurry to form a second concentrated polymer slurry in the re-slurry mixer that can be pumped to a second slurry loop reactor.