Hydroisomerization Reactor with In-Situ Catalyst Stage
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Solution Overview
Problem
Conventional systems for selective hydroisomerization of 1-butene to 2-butene in C4 streams are inefficient, leading to lower yields of 2-butene and higher catalyst usage, with significant losses of butenes to butanes, and require large, costly distillation towers with high reflux ratios.
Innovation Solution
A process involving a fixed bed hydroisomerization reactor followed by a deisobutylenizer with a catalyst stage positioned at the point of maximum driving force for hydroisomerization, using multiple hydrogen streams and carbon monoxide to inhibit hydrogenation reactions, thereby increasing 2-butene yield and reducing butane formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional fixed bed hydroisomerization is used to convert 1-butene to 2-butene, then 2-butene production occurs, but significant losses of butenes to butanes occur and catalyst usage increases
Solution Approach 1:
The patent applies preliminary action by performing selective hydrogenation of butadiene to 1-butene before the main hydroisomerization step. This pre-treatment removes competing reactions that would otherwise consume hydrogen and catalyst during hydroisomerization, thereby reducing butane formation losses and improving 2-butene yield. The sequence of operations is deliberately arranged to prepare the feedstock in advance for the main conversion process.
Solution Approach 2:
The patent employs parameter changes by carefully controlling temperature, pressure, and hydrogen-to-feed ratio across different reactor stages. By optimizing these parameters specifically for hydroisomerization rather than hydrogenation, the process maximizes 2-butene production while minimizing butane formation. The parameters are adjusted to favor the desired reaction pathway and reduce unwanted side reactions.
2Manufacturing precision
If conventional distillation towers with high reflux ratios are used for separation, then purification is achieved, but operational costs increase
Solution Approach 1:
The patent merges the reaction and separation functions into an integrated catalytic distillation system. The distillation tower incorporates catalyst stages that perform hydroisomerization reactions in-situ within the separation column. This combination allows the reaction to occur at different locations within the tower where local compositions favor 2-butene production, while the distillation simultaneously separates and concentrates the product, reducing the need for high reflux ratios and external purification steps.
3Productivity
If conventional catalytic systems are used for hydroisomerization, then conversion occurs, but catalyst requirements increase
Solution Approach 1:
The patent segments the catalytic function into multiple distinct stages with different catalyst types and functions. The first stage uses a selective hydrogenation catalyst to convert butadiene to 1-butene, while subsequent stages use hydroisomerization catalysts to convert 1-butene to 2-butene. Each catalyst is optimized for its specific function and placed at the appropriate location in the process, allowing smaller quantities of highly active catalysts to achieve high overall conversion rates.
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 approach enhances the selectivity of 2-butene production, reduces catalyst requirements, and minimizes butane formation, resulting in improved efficiency and lower operational costs compared to conventional methods.
Implementation Method 1
contacting the stream with a noble metal catalyst
Implementation Method 2
The primary hydrogenation reaction of butadiene plus hydrogen forms 1-butene
Implementation Method 3
separating the hydroisomerization effluent in a fractionation column
Data Source
AI summary
A process is disclosed for the preferential conversion to 2-butene of a C4 stream containing 1-butene and 2-butene. The process involves mixing the C4 stream with a first hydrogen stream to form a feed stream, hydroisomerizing the feed stream in the presence of a first hydroisomerization catalyst in order to convert at least a portion of the 1-butene to 2-butene, thereby producing a hydroisomerization effluent, separating the hydroisomerization effluent in a fractionation column having an upper end and a lower end to form a 1-butene mixture at the upper end, a top effluent stream containing isobutane and isobutylene and a bottoms stream containing 2-butene, and hydroisomerizing the 1-butene mixture at the upper end of the column using a second hydroisomerization catalyst. A corresponding apparatus also is disclosed.