Bio Isobutene Production via Ethylene Dimerization and Skeletal Isomerization
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Solution Overview
Problem
The production of high purity isobutene from renewable sources is energy intensive and typically relies on non-renewable feedstocks, necessitating the development of processes that convert bio-derived ethanol into high purity isobutene efficiently while avoiding fossil-based intermediates.
Innovation Solution
A system comprising dehydration, dimerization, skeletal isomerization, and catalytic separation units converts bio-ethanol into high purity isobutene, utilizing bio-ethylene dimerization to produce n-butenes, followed by skeletal isomerization to form a C4 mixture, and finally catalytic separation to isolate isobutene, with optional oxygenate/back-cracking steps for enhanced purification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional processes are used to produce high purity isobutene, then isobutene purity can be achieved, but energy consumption is excessive and non-renewable feedstocks are required
Solution Approach 1:
The process changes the chemical parameters and reaction conditions through a multi-step transformation pathway (dehydration of ethanol to ethylene, dimerization to n-butenes, skeletal isomerization to isobutene) rather than direct conversion, allowing for better control of energy input at each stage and achieving high purity isobutene with reduced overall energy consumption compared to conventional routes
Solution Approach 2:
The process extracts and removes byproducts and impurities at each stage through selective reaction pathways and separation units, ensuring high purity isobutene production while the renewable ethanol feedstock replaces non-renewable petroleum-based feedstocks, eliminating the need for fossil-based intermediates
2Manufacturing precision
If conventional processes are used to produce high purity isobutene, then isobutene purity can be achieved, but non-renewable feedstocks are required
Solution Approach 1:
The process fundamentally changes the feedstock parameter from non-renewable petroleum-based feedstocks to renewable bio-ethanol, while maintaining isobutene purity through controlled reaction conditions and separation processes. This parameter change enables green certification and sustainability while achieving the required product specifications
Solution Approach 2:
The conversion process is segmented into distinct unit operations (dehydration, dimerization, skeletal isomerization, separation) that can each be optimized for renewable feedstock processing, allowing the system to adapt to bio-based inputs while maintaining high purity isobutene output
3Adaptability or versatility
If multi-step conversion process is used to convert bio ethanol to isobutene, then renewable feedstock utilization is improved, but process complexity increases
Solution Approach 1:
The complex conversion process is divided into modular unit operations (dehydration unit, dimerization unit, skeletal isomerization unit, separation unit), each performing a specific function. This segmentation allows for easier design, operation, and maintenance while enabling efficient utilization of renewable ethanol feedstock to produce isobutene
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 high purity isobutene production with reduced energy intensity and minimal byproduct formation, specifically producing isobutene with purities up to 99.9% wt% using renewable bio-derived ethanol, meeting 'green' certification standards by excluding fossil-based intermediates.
Implementation Method 1
a dehydration unit configured to receive a bio ethanol containing stream, convert the bio ethanol to bio ethylene
Implementation Method 2
a dimerization unit configured to receive the bio ethylene stream, dimerize ethylene
Implementation Method 3
a skeletal isomerization unit configured to receive the n-butenes containing stream, convert n-butenes to produce a skeletal isomerization stream comprising an isobutene
Implementation Method 4
a catalytic separation unit configured to receive the skeletal isomerization stream, convert olefins and/or isoolefins contained therein to produce a converted skeletal isomerization reaction product, and to fractionate the skeletal isomerization reaction product to produce a bio isobutene product fraction
Data Source
AI summary
A process and system for converting bio ethanol to high purity isobutene is provided. The system includes a dehydration unit configured to receive a bio ethanol containing stream, convert the bio ethanol to bio ethylene, and produce a bio ethylene containing stream, a dimerization unit configured to receive the bio ethylene stream, dimerize ethylene, and produce an n-butenes containing stream, a skeletal isomerization unit configured to receive the n-butenes containing stream, convert n-butenes to produce a skeletal isomerization stream comprising an isobutene, isobutane, n-butenes, and n-butane, and a catalytic separation unit configured to receive the skeletal isomerization stream, convert olefins and/or isoolefins contained therein to produce a converted skeletal isomerization reaction product, and to fractionate the skeletal isomerization reaction product and produce bio isobutene.