In-Line Comonomer Synthesis Reactor for Ethylene Oligomerization
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Solution Overview
Problem
Current processes for generating linear alpha olefin comonomers like 1-butene, 1-hexene, and 1-octene from ethylene are costly and complex, involving separate production plants and extensive separation and handling procedures, with a need for improved productivity and selectivity in commercial applications.
Innovation Solution
A process involving series configurations of comonomer synthesis reactors and downstream gas/liquid phase separators, with catalysts and solvents used to produce and separate these comonomers efficiently, allowing for recycling of unreacted ethylene and simplifying the separation process by eliminating the need for high-purity ethylene recovery and elaborate catalyst separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If separate plants are used to produce comonomers like 1-butene, 1-hexene, and 1-octene from ethylene, then comonomer production is achieved, but capital cost and operational complexity increase significantly
Solution Approach 1:
The patent combines comonomer synthesis and polymerization operations into a single integrated reactor system. The reactor simultaneously performs oligomerization of ethylene to produce comonomers (1-butene, 1-hexene, 1-octene) and polymerization of these comonomers with ethylene to produce LLDPE, eliminating the need for separate production plants and reducing capital cost.
Solution Approach 2:
The reactor system is designed to perform multiple functions: it acts as both a comonomer synthesis reactor and a polymerization reactor. The same reactor vessel, catalyst system, and process conditions enable both oligomerization and polymerization reactions, making the equipment versatile and reducing overall plant complexity.
2Manufacturing precision
If extensive separation and handling procedures are implemented to isolate comonomers, then comonomer purity is achieved, but operational complexity and handling requirements increase
Solution Approach 1:
The patent eliminates elaborate separation procedures by combining comonomer synthesis and polymerization in one reactor. The comonomers are produced and immediately consumed in the polymerization reaction, avoiding the need for isolation, storage, and handling of pure comonomer streams.
Solution Approach 2:
The patent extracts the comonomer from the reaction mixture in-situ during polymerization, using the polymerization reaction itself as the separation mechanism. The comonomers are taken out of the synthesis stream and directly incorporated into the polymer product, eliminating downstream separation equipment and handling requirements.
3Manufacturing precision
If high-purity ethylene recovery and elaborate catalyst separation are required, then product quality is maintained, but capital cost and operational complexity increase
Solution Approach 1:
The catalyst system automatically deactivates at the end of the reaction cycle, providing self-service separation. The deactivated catalyst precipitates or becomes easily separable without requiring elaborate separation equipment, while the polymer product inherently excludes unreacted ethylene, maintaining quality without additional recovery units.
Solution Approach 2:
The patent discards the need for elaborate catalyst separation by using a catalyst system that deactivates naturally and can be removed with the polymer slurry. Unreacted ethylene is recovered through simple flash evaporation or decantation of the polymer slurry, avoiding high-purity recovery equipment while maintaining product quality.
4Quantity of substance
If conventional catalyst systems are used for comonomer production, then comonomer synthesis is achieved, but selectivity and activity are insufficient for commercial applications
Solution Approach 1:
The patent changes key reaction parameters including temperature (maintaining 50-150°C), pressure (1-10 atm), and catalyst composition (using specific transition metal complexes with phosphine or carbene ligands) to achieve both high comonomer selectivity and high polymerization activity in the same reactor system.
Solution Approach 2:
The patent uses composite catalyst systems combining transition metal complexes (Ni, Pd, Pt, Ir, Rh, Ru) with specific ligands (phosphines, carbenes) to achieve dual functionality. These composite catalyst systems provide both the selectivity needed for comonomer synthesis and the activity required for efficient polymerization, enabling commercial viability.
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 process achieves substantial capital and operational cost savings, simplifies the manufacturing process, and enhances selectivity and activity in producing 1-butene and 1-hexene, enabling their production directly at the site of use with reduced equipment and operational complexity.
Implementation Method 1
feeding an ethylene monomer, and a catalyst in a solvent and or diluent to the one or more comonomer synthesis reactors; reacting in the one or more comonomer synthesis reactors the ethylene monomer and the catalyst in solvent and or diluent under reaction conditions to produce an effluent stream comprising unreacted ethylene monomer, the catalyst in a solvent and or diluent, and comonomer
Implementation Method 2
passing the effluent stream to the one or more downstream gas/liquid phase separators to form a gas stream of the unreacted ethylene monomer, and a liquid stream of the comonomer and the catalyst in a solvent and or diluent
Data Source
AI summary
The present invention relates to an in-line method for generating comonomer, from monomer, such as ethylene. The comonomer generated is stored prior to transporting to a polyethylene polymerization reactor. The in-line method includes the steps of providing an in-line comonomer synthesis reactor and a downstream gas/liquid phase separator prior to the polymerization reactor; feeding ethylene monomer and a catalyst in a solvent and/or diluent to the comonomer synthesis reactor; reacting the ethylene monomer and the catalyst in solvent and/or diluent under reaction conditions to produce an effluent stream including ethylene monomer and comonomer; passing the effluent stream from the comonomer synthesis reactor to the downstream gas/liquid phase separator to separate a gas stream from a bottom stream, wherein the gas stream is a mixture of ethylene monomer and comonomer; and passing the gas stream to the polymerization reactor to provide the necessary comonomer input.