Isobutylene Production via Bromination-Dehydrobromination
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Solution Overview
Problem
Current methods for producing isobutylene and isoamylene from mixed alkanes are inefficient, requiring multiple extraction steps and relying on external olefins, while existing processes for isobutane dehydrogenation and steam cracking are costly and resource-intensive.
Innovation Solution
A method involving bromination of butane and pentane streams to form bromides, followed by isomerization and dehydrobromination, using silica-based catalysts or non-catalytic processes to produce isobutylene and isoamylene, with optional hydrogenation and recycling steps to enhance yield and separation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional extraction steps are used to separate isobutylene from crude C4 stream, then isobutylene can be obtained, but the process requires multiple complex extraction steps and is resource-intensive
Solution Approach 1:
The invention changes the chemical state of isobutane by brominating it to form t-butyl bromide, which has different separation properties. This parameter change (from alkane to alkyl bromide) enables simpler separation processes and eliminates the need for multiple complex extraction steps while maintaining reliable isobutylene production
Solution Approach 2:
The invention introduces bromine as an intermediary substance that temporarily converts isobutane to t-butyl bromide. This intermediary compound serves as a separation mediator that can be easily separated from other C4 components, simplifying the overall process while maintaining product purity
2Productivity
If iBDH process is used for isobutylene production, then isobutylene can be produced from isobutane, but separation and recovery require reacting with alcohol to form ether and subsequent cracking steps
Solution Approach 1:
The invention uses bromine as an intermediary to convert isobutane to t-butyl bromide, which then serves as a separable intermediate. This intermediary approach replaces the complex alcohol-ether-cracking sequence with a simpler bromide formation and separation process, reducing equipment complexity while maintaining productivity
Solution Approach 2:
The invention extracts the separation function by converting isobutane to t-butyl bromide, which can be separated from the reaction mixture through simple distillation or phase separation. This extraction of the separation step from the overall process eliminates the need for alcohol reaction and ether cracking equipment
3Quantity of substance
If steam cracking process is used for olefin production, then olefins can be produced, but the process is costly and requires external feedstock
Solution Approach 1:
The invention enables the system to serve itself by using bromine that can be regenerated from HBr produced during dehydrobromination. This self-service approach eliminates the need for external olefin feedstock and reduces energy consumption by avoiding the high-temperature steam cracking process, as the bromination-dehydrobromination sequence occurs at lower temperatures
4Reliability
If traditional alkylation process is used, then alkanes of sufficient octane number can be produced, but external olefins must be obtained from other processes
Solution Approach 1:
The invention makes the bromination-dehydrobromination system universal by enabling it to produce both isobutylene and provide HBr for bromine regeneration. This multi-functional approach allows the same chemical system to serve both olefin production and bromine cycling functions, improving process integration and eliminating dependence on external olefin sources
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 method effectively produces isobutylene and isoamylene with improved yield and separation efficiency, reducing the need for external olefins and minimizing resource consumption, thereby enhancing the overall process efficiency and cost-effectiveness.
Implementation Method 1
brominating a butanes feed stream comprising i-butane in a bromination reactor to form a bromination effluent stream comprising t-butyl bromide
Implementation Method 2
isomerizing at least a portion of the n-butane to form an isomerization effluent comprising i-butane and n-butane
Implementation Method 3
dehydrobrominating the t-butyl bromide to form isobutylene and HBr
Implementation Method 4
separating the butanes from the bromination effluent stream to form a brominated compound stream
Implementation Method 5
hydrogenating the polybromides to form a hydrogenation recycle stream
Data Source
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AI summary
A method includes brominating a butanes feed stream including i-butane in a bromination reactor to form a bromination effluent stream including t-butyl bromide. The method includes dehydrobrominating the t-butyl bromide to form isobutylene. Another method includes brominating a mixed pentanes feed stream including i-pentane and n-pentane in a bromination reactor to form a bromination effluent stream including t-pentyl bromide. The method includes dehydrobrominating the t-pentyl bromide to form isoamylene and HBr.