Cascade Reactor Oligomerization Selectivity
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Solution Overview
Problem
Existing oligomerization processes using single bubble point reactors are limited in achieving high levels of selectivity and conversion for ethylene, unable to simultaneously optimize both parameters without changing reactor technology.
Innovation Solution
A process employing a cascade of N stirred gas/liquid reactors, where a homogeneous catalytic system is introduced into the first reactor, and ethylene is introduced into the lower part, with a liquid fraction recirculated and cooled before reintroduction into subsequent reactors, allowing for improved selectivity and conversion of ethylene to linear alpha-olefins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single bubble point reactor is used for oligomerization, then the process is simple to operate, but the selectivity for olefins and conversion of ethylene cannot simultaneously achieve high levels
Solution Approach 1:
The invention divides a single reactor system into multiple bubble point reactors connected in series (cascade configuration). Each reactor stage contributes to the overall oligomerization process, allowing the system to achieve high conversion while maintaining high selectivity for linear alpha-olefins. The segmentation enables progressive reaction stages that overcome the limitations of a single reactor.
2Manufacturing precision
If the number of reactors in cascade is increased to improve selectivity and conversion, then the performance ceiling is exceeded, but the device complexity increases
Solution Approach 1:
The invention merges multiple bubble point reactors into a unified cascade system where each reactor shares the same fundamental design and operating principles. The reactors are connected in series with liquid effluent from one reactor becoming the feed for the next, creating an integrated system that achieves high performance without proportionally increasing complexity. The standardized modular design allows for efficient integration.
3Productivity
If ethylene flow rate is increased to improve productivity, then the conversion efficiency decreases, but if ethylene flow rate is decreased to improve conversion, then productivity is reduced
Solution Approach 1:
The invention implements continuous liquid recirculation through the cascade of reactors, where the liquid effluent from each reactor is fed to the next reactor in sequence. This continuous action allows ethylene to undergo progressive oligomerization across multiple stages, maintaining high conversion efficiency even at increased flow rates. The continuous recirculation ensures that reactants are fully utilized while preserving high productivity.
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 enhances selectivity and conversion of ethylene to linear alpha-olefins, such as but-1-ene, hex-1-ene, or oct-1-ene, while reducing implementation costs, achieving superior performance compared to single-reactor systems.
Implementation Method 1
a first, "main", part of the liquid fraction, which is conveyed to a heat exchanger for cooling
Implementation Method 2
introducing a homogeneous catalytic oligomerization system comprising at least one metal precursor, optionally at least one activator and optionally at least one additive
Data Source
AI summary
The invention relates to a process for the oligomerization of ethylene, carried out at a pressure of between 0.1 and 10.0 MPa, at a temperature of between 30 and 200° C., in a cascade of N gas/liquid reactors in series, N being at least equal to 2, comprising a step of introducing a catalytic oligomerization system into at least the first reactor of the cascade, a step of bringing said catalytic system and an optional solvent into contact with ethylene by introducing said ethylene into the lower part of the reaction chamber of at least the first reactor of the cascade, for each reactor n, a step of withdrawing a liquid fraction in the lower part of the reaction chamber of the reactor n, the liquid fraction being separated into two streams: a first stream corresponding to a first, “main”, part of the liquid fraction, which is conveyed to a heat exchanger for cooling; a second stream corresponding to the second part of the liquid fraction which constitutes the liquid feedstock of the following reactor n+1 in the cascade, a step of introducing said second part of the liquid phase withdrawn from the reactor n towards the reaction chamber of the following reactor n+1 in the direction of flow, a step of cooling said first part of the liquid fraction withdrawn from the reactor n in step c) by passing said first part of the liquid fraction into a heat exchanger in order to obtain a cooled liquid fraction, a step of introducing said liquid fraction cooled in step e) at the top of the reaction chamber of said reactor n, the steps a) to f) being carried out, unless indicated otherwise, for each reactor n of the cascade, n being between 1 and N. The invention also relates to a device of N stirred gas/liquid reactors in a cascade, enabling the oligomerization process to be carried out.