Reactive Distillation for Olefin Feedstock Purification
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Solution Overview
Problem
Existing methods fail to effectively treat olefinic feedstocks with high tertiary branched olefin content to produce an effluent with less than 3% tertiary branched olefins, which is necessary for metathesis reactions, particularly from the dehydration of alcohols using zeolite catalysts.
Innovation Solution
A reactive distillation process with a specific column configuration, including a reflux zone, intermediate reaction zone with catalytic beds, and a lower fractionation zone, operated at controlled pressure and temperature, fed with an olefinic feedstock and an alcohol feedstock to achieve the desired separation and conversion of tertiary branched olefins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional separation methods (distillation, extraction) are used to remove tertiary branched olefins, then the olefinic effluent can meet metathesis specifications, but the process complexity and cost increase significantly
Solution Approach 1:
The patent combines reaction and separation into a single reactive distillation column. The conversion of tertiary branched olefins to linear olefins occurs within the column itself through catalytic reaction, while simultaneous distillation separates the products. This integration eliminates the need for separate reaction and separation units, reducing overall process complexity while achieving the required effluent purity for metathesis reactions
Solution Approach 2:
The patent changes the chemical composition parameters within the distillation column by introducing an alcohol feedstock that reacts with tertiary branched olefins. This chemical transformation converts unwanted branched olefins into desired linear olefins, fundamentally changing the composition of the olefinic effluent to meet specifications without requiring complex physical separation processes
2Manufacturing precision
If multiple reaction steps (oligomerization followed by etherification) are used to remove isobutene, then isobutene content can be reduced to 0.57%, but the process time and operational complexity increase
Solution Approach 1:
The patent merges multiple reaction steps into a single integrated process. Instead of performing oligomerization followed by etherification in separate reactors, the reactive distillation column performs the conversion of tertiary branched olefins to linear olefins in one continuous operation, significantly reducing process time while achieving comparable or superior removal efficiency
Solution Approach 2:
The reactive distillation column operates continuously with the conversion reaction occurring throughout the column height. The alcohol feedstock continuously reacts with tertiary branched olefins as they pass through the catalytic zones, maintaining continuous conversion action without the need for batch processing or intermediate separation steps, thereby reducing overall process time
3Manufacturing precision
If catalytic distillation is used to isomerize 1-butene into 2-butene and separate it, then separation can be achieved, but the quality of isobutene/2-butene separation and yield of n-butenes recovered are insufficient
Solution Approach 1:
Instead of relying on physical property differences for separation, the patent changes the chemical identity of the unwanted component by converting tertiary branched olefins into linear olefins through chemical reaction. This parameter change in chemical composition allows the desired linear olefins to be produced in-situ, eliminating the need for complex separation and improving recovery yield
Solution Approach 2:
The patent converts the harmful presence of tertiary branched olefins (which need to be removed) into a beneficial outcome by chemically transforming them into the desired linear olefins. This conversion turns a separation problem into a production opportunity, simultaneously removing unwanted components and generating valuable products, thereby improving both separation quality and recovery yield
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 process achieves an olefinic effluent with less than 3% tertiary branched olefins, meeting metathesis feedstock specifications while minimizing primary alcohol losses and maintaining reasonable costs.
Implementation Method 1
A reactive distillation process with a specific column configuration, including a reflux zone, intermediate reaction zone with catalytic beds, and a lower fractionation zone
Implementation Method 2
intermediate reaction zone with catalytic beds
Data Source
AI summary
The present invention relates to a process for treating, by reactive distillation, an olefinic feedstock comprising linear olefins containing n carbon atoms, and branched olefins, the branched olefins comprising tertiary branched olefins, for example a mixture of n-butenes and of tertiary branched olefins comprising isobutene, so as to produce an olefinic effluent with a mass content of tertiary branched olefin of less than or equal to 3% by weight and a heavy hydrocarbon effluent, said process comprising the feeding of a reactive distillation section with said olefinic feedstock and with an alcohol feedstock comprising a primary alcohol, said reactive distillation section comprising a column composed at least of an upper reflux zone into which is introduced said alcohol feedstock, comprising, for example, ethanol, an intermediate reaction zone comprising at least 6 reactive doublets, and a lower fractionation zone at the level of which said section is fed with said olefinic feedstock, said reactive distillation section being operated at a relative pressure of between 0.3 and 0.5 MPa, a column head temperature of between 40° C. and 60° C., with a reflux ratio of between 1.8 and 2.2.