Catalytic Distillation for C5 Olefin Dimerization
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Solution Overview
Problem
Existing isoolefin dimerization and etherification processes face challenges with catalyst deactivation, side reactions, and the need for complex separation processes due to impurities and additives, leading to reduced selectivity and efficiency.
Innovation Solution
A process involving a selective hydrogenation unit followed by a series of fixed bed and catalytic distillation reactors using catalysts configured for both dimerization and etherification, with oxygenate moderators to control reaction pathways, allowing for flexible production of dimers or ethers without the need for intermediate depentanizers and minimizing catalyst poisoning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional dimerization catalysts are used, then dimerization reaction occurs, but catalyst deactivation due to poisoning and fouling from impurities reduces catalyst life and requires frequent shutdowns
Solution Approach 1:
The patent applies preliminary action by implementing a selective hydrogenation unit before the dimerization reactor to convert dienes to olefins. This pre-treatment removes catalyst poisons (dienes) from the feed stream before they can deactivate the dimerization catalyst, thereby extending catalyst life and maintaining stable catalyst activity without frequent shutdowns
Solution Approach 2:
The patent uses an intermediary approach by introducing a selective hydrogenation unit as a mediator between the feed stream and the dimerization catalyst. This intermediary unit selectively converts harmful dienes to less harmful olefins, protecting the main dimerization catalyst from poisoning while allowing the dimerization reaction to proceed
2Manufacturing precision
If additives are used to promote dimer selectivity, then dimerization selectivity improves, but unwanted acid throw deactivates the catalyst and complicates separation processes
Solution Approach 1:
The patent applies the taking out principle by removing the need for additive-based selectivity control. Instead of adding moderators that cause acid throw and require complex separation, the process achieves high dimer selectivity through optimized catalyst selection and reaction conditions, effectively extracting the harmful additives from the system
Solution Approach 2:
The patent replaces expensive, problematic additives with a more economical approach using stable catalysts and moderate process conditions. The solution avoids using vulnerable additives that require complex recovery systems, instead relying on inherent catalyst selectivity that doesn't require additional separation equipment
3Productivity
If conventional fixed bed reactors are used, then dimerization occurs, but side reactions and catalyst fouling reduce efficiency and require frequent maintenance
Solution Approach 1:
The selective hydrogenation unit performs preliminary action by converting dienes to olefins before the dimerization reaction. This pre-treatment prevents catalyst fouling and side reactions in the fixed bed reactor, maintaining high dimerization efficiency and eliminating the need for frequent reactor shutdowns for maintenance
Solution Approach 2:
The patent converts the harmful effect of dienes (which cause catalyst fouling and reduce efficiency) into a benefit by using selective hydrogenation to transform them into desirable olefins. This converts a harmful impurity into a useful reactant, improving dimerization efficiency while eliminating the need for frequent maintenance shutdowns
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 catalyst life, reduces unwanted byproducts, and achieves high selectivity and conversion of isoolefins to dimers and ethers, enabling flexible production without the need for frequent reactor shutdowns or changes in catalysts.
Implementation Method 1
a selective hydrogenation unit configured to convert the dienes to olefins
Implementation Method 2
a first fixed bed reactor containing a first catalyst, producing a first reactor effluent comprising dimers of the isoolefin
Implementation Method 3
a catalytic distillation reactor system configured to separate the first reactor effluent into a C5 stream and a first bottoms stream
Data Source
AI summary
A process for the selective dimerization and etherification of isoolefins. The process including feeding a mixed C5 stream to a selective hydrogenation unit to convert dienes to olefins and isoolefins, producing a hydrogenated effluent stream. The hydrogenated effluent stream is fed to a first fixed bed reactor, producing a first reactor effluent. The first reactor effluent is fed to a catalytic distillation reactor system, producing a first overheads including unreacted olefins, isoolefins, oxygenate, and one or more C5 ethers and a first bottoms including dimers of the isoolefins, any produced trimers of the isoolefins, and heavy oxygenates. The first overheads is fed to a second fixed bed reactor, producing a second reactor effluent including dimers of the isoolefins, unreacted C5s, and unreacted oxygenates. The first bottoms stream and the second reactor effluent are combined and fed to a product splitter, producing a second overheads stream including unreacted C5 olefins, isoolefins, and oxygenates and a second bottoms stream including C10+ hydrocarbons.