Field Butane Separation Pathways for Ethylene and MTBE Output
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Solution Overview
Problem
Existing processes face challenges in achieving the required purity and volume of fuel additives like MTBE and butanol, and efficiently utilizing components in mixed C4 hydrocarbon streams from steam crackers, leading to inefficiencies and increased costs.
Innovation Solution
A process and system that separates n-butane and isobutane from field butane, cracks n-butane to produce ethylene, separates butenes for butanol production, and dehydrogenates isobutane to form alkyl tert-butyl ether, optimizing the MTBE production plant capacity and cracker feed handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If MTBE is produced by reaction of isobutene with methanol, then the octane rating of gasoline is increased, but the process faces challenges in achieving required purity and volume
Solution Approach 1:
The process segments the C4 hydrocarbon stream into separate n-butane and isobutane streams through fractionation, allowing independent optimization of each pathway. The n-butane stream is cracked to ethylene while the isobutane stream is dehydrogenated to isobutene for MTBE production, enabling simultaneous improvement of purity and volume by directing specific components to appropriate reaction pathways.
Solution Approach 2:
The process changes the chemical composition parameters of the feedstock by converting n-butane to isobutane through isomerization, and subsequently converting isobutane to isobutene through dehydrogenation. These parameter changes enable the feedstock to undergo different reaction pathways that optimize both purity and production volume of MTBE.
2Productivity
If mixed C4 hydrocarbons are separated into individual components, then the financial benefits are increased, but the separation process presents technical and financial challenges
Solution Approach 1:
The process divides the mixed C4 hydrocarbon stream into separate n-butane and isobutane streams using fractionation units. This segmentation allows each component to be processed independently through optimized pathways (cracking for n-butane, dehydrogenation for isobutane), maximizing financial benefits while managing complexity through modular process design.
Solution Approach 2:
The process creates a multi-functional system where the same separation infrastructure serves multiple purposes: separating C4 components for different product pathways, managing recycle streams from steam crackers, and providing feedstock for both ethylene production and MTBE synthesis. This universality reduces overall system complexity despite the multiple functions performed.
3Productivity
If cracker feed handling capacity is increased, then the production capacity of MTBE plants is enhanced, but the process requires optimized separation and reaction pathways
Solution Approach 1:
The process segments the cracker feed into n-butane and isobutane streams, allowing the cracker to handle higher overall feed capacities while maintaining product quality. The segmented streams can be processed through optimized reaction pathways (cracking and dehydrogenation) that maximize MTBE production capacity without compromising separations or requiring excessive process complexity.
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 enhances the production capacity of MTBE plants and improves cracker feed handling by producing high-purity ethylene, butanol, and alkyl tert-butyl ether with high octane numbers and low impurities, reducing capital costs and improving efficiency.
Implementation Method 1
separating the field butane into an n-butane stream and an isobutane stream
Implementation Method 2
cracking the n-butane stream to obtain ethylene and a cracked product stream comprising n-butane, 1-butene, 2-butene, butadienes
Implementation Method 3
dehydrogenating the isobutane stream in a dehydrogenation unit to form an isobutene stream
Implementation Method 4
reacting the butene stream with water to obtain a fuel additive comprising butanol
Implementation Method 5
reacting the isobutene stream with an aliphatic alcohol to produce an alkyl tert-butyl ether
Data Source
AI summary
A process for producing ethylene and at least one of butanol and an alkyl tert-butyl ether from field butane includes separating the field butane into an n-butane stream and an isobutane stream; cracking the n-butane stream to obtain a cracked product stream comprising n-butane, 1- butene, 2-butene, butadienes, or a combination comprising at least one of the foregoing; and at least one of the following: (1) separating the cracked product stream to obtain a butane stream and a butene stream, and reacting the butene stream with water to obtain a fuel additive comprising butanol, and (2) dehydrogenating the isobutane stream in a dehydrogenation unit to form an isobutene stream and reacting the isobutene stream with an aliphatic alcohol to produce an alkyl tert-butyl ether.