Integrated Butadiene Recovery via Extractive Solvent Separation
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Solution Overview
Problem
Current butadiene production processes in petrochemical plants face inefficiencies in recovering butadiene, particularly due to the heating of butadiene and the separation steps between non-oxidative and oxidative dehydrogenation processes, which affect the economics of production.
Innovation Solution
A process integrating dehydrogenation and oxydehydrogenation units with extractive solvent systems, including butane extraction and light gas separation columns, to enhance butadiene recovery by separating and recycling butenes and butadiene streams efficiently, utilizing solvents like n-methylpyrrolidone and operating at specific temperatures to optimize separation and recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If butadiene is heated and separated through multiple extraction columns, then butadiene recovery is improved, but process complexity and energy consumption increase
Solution Approach 1:
The patent combines the non-oxidative dehydrogenation unit and oxidative dehydrogenation unit into an integrated process flow, where the output of the first unit directly feeds into the second unit without separate heating and cooling steps. This merging eliminates redundant thermal processing steps and reduces overall process complexity while maintaining high butadiene recovery through the integrated extraction system.
Solution Approach 2:
The patent implements continuous operation where butenes are continuously separated and fed from the non-oxidative dehydrogenation unit to the oxidative dehydrogenation unit without interruption. The extraction columns operate continuously to separate butadiene from the process stream, maintaining steady-state operation that improves recovery efficiency while reducing the need for repeated heating and cooling cycles.
2Measurement precision
If multiple extraction columns are used to separate butenes and butadiene, then separation efficiency is improved, but energy consumption increases
Solution Approach 1:
The patent utilizes changes in solvent properties and operating conditions across different extraction columns to optimize separation. The first extraction column operates with specific temperature and solvent composition parameters to separate butenes, while the second extraction column uses different parameters to separate butadiene. This parameter optimization allows efficient separation while minimizing energy consumption by avoiding excessive heating or cooling.
Solution Approach 2:
The patent introduces extractive solvents as intermediary substances that facilitate the separation of butenes and butadiene. These solvents selectively interact with the hydrocarbon components, enabling separation at lower energy costs compared to direct thermal separation. The solvents act as mediators that enhance separation efficiency without requiring high energy input for multiple distillation columns.
3Productivity
If butenes are separated and fed to oxidative dehydrogenation, then butadiene yield is improved, but process time increases
Solution Approach 1:
The patent implements preliminary separation of butenes from the dehydrogenation product stream before feeding to the oxidative dehydrogenation unit. This preliminary action ensures that only the desired butene components are subjected to further processing, improving butadiene yield by preventing side reactions. The continuous operation of the extraction columns maintains this preliminary separation without significant time delay.
Solution Approach 2:
The patent maintains continuous operation throughout the process, with butenes being continuously separated and fed to the oxidative dehydrogenation unit without batch processing interruptions. This continuous flow minimizes idle time between separation and conversion steps, improving overall process time efficiency while maintaining high butadiene yield through uninterrupted reaction conditions.
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 significantly improves butadiene recovery by increasing the concentration of butenes and reducing undesirable feed to oxidative dehydrogenation, thereby enhancing the economic viability of butadiene production and improving overall plant economics.
Implementation Method 1
passing the first n-butene process stream to a butane extraction column to generate a butane overhead stream and a first n-butene stream, wherein the butane extraction column is operated to recover the n-butenes in the first butene stream
Implementation Method 2
passing the second stream to a light gas separation unit to generate a vapor phase comprising hydrogen, and a third stream comprising liquid n-butane and n-butene
Implementation Method 3
passing the overhead stream to an oxydehydrogenation unit to generate a second process stream comprising n-butene and butadiene
Data Source
AI summary
A process for the production of butadiene is presented. The process combines the separation of butenes and butadienes extracted from a non-oxidated dehydrogenation process with the separation of butenes and butadienes from an oxidative dehydrogenation process to increase the butadiene yields and reduce the equipment for the recovery of a butadiene product.