C4 Stream Isobutene Purification by 1-Butene Isomerization
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Solution Overview
Problem
Existing processes for purifying isobutene from a C4 stream face challenges due to the close boiling points of isobutene and 1-butene, leading to high energy consumption and insufficient purity for specific applications, particularly when 1-butene is isomerized to 2-butene, resulting in excessive 1-butene content in the product stream.
Innovation Solution
A process involving an isomerization reactor with a hydrogenation-active catalyst on an aluminum oxide support converts 1-butene to 2-butene, followed by rectification columns to separate isobutene, using multiple stages and catalysts to achieve high purity, with optional additional rectification steps to further refine the isobutene stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distillation is used to separate isobutene from 1-butene, then separation is achieved, but energy consumption is high due to close boiling points
Solution Approach 1:
The patent changes the chemical composition parameter by isomerizing 1-butene to 2-butene, which has a significantly different boiling point from isobutene. This parameter change enables easier separation through distillation or extractive distillation, reducing the energy consumption associated with separating compounds with close boiling points.
Solution Approach 2:
The patent introduces an isomerization step as an intermediary process that converts 1-butene to 2-butene before separation. This intermediary transformation creates a more favorable separation scenario by increasing the boiling point difference between the components to be separated.
2Ease of operation
If 1-butene is isomerized to 2-butene to facilitate separation, then separation becomes easier, but 1-butene content in the product stream becomes too high for specific applications
Solution Approach 1:
The patent segments the separation process into multiple stages: first isomerizing 1-butene to 2-butene, then performing separation to obtain an intermediate product stream, and finally conducting a second isomerization followed by another separation stage. This segmentation allows each stage to be optimized for its specific function, achieving both ease of separation and high product purity.
Solution Approach 2:
The patent employs periodic or repeated cycles of isomerization and separation operations. By alternating between isomerization reactions and separation processes, the system progressively reduces 1-butene content while maintaining efficient operation, ultimately achieving the required product purity specification.
3Manufacturing precision
If multiple isomerization and fractionation stages are used to increase isobutene purity, then purity improves, but energy consumption significantly increases
Solution Approach 1:
The patent strategically changes the chemical parameter of the butene isomers by selective isomerization, converting 1-butene to 2-butene which has more favorable separation characteristics. This parameter change enables more energy-efficient separation operations in subsequent stages compared to directly separating 1-butene from isobutene.
Solution Approach 2:
The patent performs preliminary isomerization of 1-butene to 2-butene before the main separation operation. This preliminary action prepares the mixture for more energy-efficient separation by creating a larger boiling point difference, thereby reducing the energy consumption of the subsequent fractionation process while achieving the required purity.
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 isobutene purity of at least 95%, preferably 98%, and particularly 99%, by effectively reducing 1-butene content through multiple isomerization and separation stages, thereby meeting the purity requirements for isobutene-containing plastics production.
Implementation Method 1
a catalyst which accelerates the isomerization of 1-butene to 2-butene
Implementation Method 2
isobutene is obtained by fractionation
Data Source
AI summary
A process for the purification of isobutene from a C4 stream with at least 1-butene, 2-butene, isobutane and isobutene includes isomerizing 1-butene from a stream of material which is concentrated in isobutane and isobutene obtained from the C4 stream into 2-butene, using a catalyst in an isomerization reactor; supplying a product stream from the isomerization reactor to a rectification column; and providing a stream of material which is concentrated in isobutene. A processing facility is utilized for the purification of isobutene from the C4 stream.