1,3-Butadiene Recovery via Selective Hydrogenation and Single Extractive Distillation
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Solution Overview
Problem
Current methods for separating highly pure 1,3-butadiene from crude C4 streams face challenges such as acetylene contamination, energy consumption, and inefficiencies in the butadiene extraction unit, leading to suboptimal recovery rates and equipment longevity issues.
Innovation Solution
A method involving selective liquid-phase hydrogenation of acetylenes in crude C4 mixtures using multiple hydrogenation reactors, followed by extractive distillation with a single extractive distillation column, and subsequent solvent recovery and purification steps to achieve high purity 1,3-butadiene recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If selective hydrogenation is performed to remove acetylenes, then acetylene contamination is reduced, but 1,3-butadiene is converted to 1-butene and propylenes causing loss of product
Solution Approach 1:
The patent applies parameter changes by optimizing hydrogenation conditions (temperature, pressure, hydrogen to acetylene ratio) to achieve selective conversion of acetylenes to 1,3-butadiene while minimizing over-hydrogenation to 1-butene and propylenes. By controlling these parameters, the process achieves high acetylene removal efficiency while maintaining 1,3-butadiene selectivity.
Solution Approach 2:
The patent implements feedback control by monitoring the composition of the hydrogenation effluent and adjusting operating parameters accordingly. The system maintains optimal conditions by feedback from product analysis to ensure acetylene conversion to desired 1,3-butadiene while preventing excessive conversion to unwanted products.
2Productivity
If the bottom temperature of 1,3-butadiene recovery column is increased to improve recovery, then recovery rate increases, but vinylacetylene explosion threshold is exceeded
Solution Approach 1:
The patent applies preliminary action by performing selective hydrogenation of acetylenes to 1,3-butadiene before the extractive distillation process. This preliminary conversion eliminates vinylacetylene from the feed stream, allowing the recovery column to operate at higher temperatures for improved butadiene recovery without explosion risk.
Solution Approach 2:
The patent converts the harmful vinylacetylene into beneficial 1,3-butadiene through selective hydrogenation. This transformation not only eliminates the explosion hazard but also increases the desired product concentration in the recovery column, simultaneously improving safety and productivity.
3Manufacturing precision
If multiple extractive distillation columns are used to separate 1,3-butadiene, then separation purity is improved, but device complexity and energy consumption increase
Solution Approach 1:
The patent applies preliminary action by removing acetylenes through selective hydrogenation before the extractive distillation process. This pre-treatment simplifies the subsequent distillation process by eliminating difficult-to-separate acetylene components, allowing high purity 1,3-butadiene recovery using fewer distillation columns.
Solution Approach 2:
The patent extracts and removes acetylenes from the C4 stream through selective hydrogenation before the extractive distillation process. This extraction of harmful components simplifies the main separation process and reduces the number of distillation columns required while maintaining high product purity.
4Productivity
If hydrogenation is performed at higher pressure and temperature to increase hydrogen solubility, then acetylene conversion efficiency improves, but energy consumption increases
Solution Approach 1:
The patent applies parameter changes by optimizing the balance between pressure and temperature in the hydrogenation process. By carefully controlling these parameters, the system achieves sufficient hydrogen solubility and acetylene conversion efficiency while minimizing energy consumption. The optimal operating conditions are determined through process optimization.
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 significantly reduces acetylene concentrations, minimizes 1,3-butadiene loss, and increases recovery rates to 98.5% or more, while reducing the number of processing units and energy consumption, thereby enhancing the overall efficiency and longevity of the extraction process.
Implementation Method 1
selective hydrogenation of acetylenes in the C4 mixtures to convert the acetylenes into 1,3-butadiene, 1-butene and propylenes, respectively
Implementation Method 2
the bottom stream of a 1,3-butadiene recovery column, which is used for recovering some 1,3-butadienes from the bottom stream of the 2nd EDC
Data Source
AI summary
Disclosed is a method of recovering 1,3-butadiene from a C4 stream containing butane, isobutane, 2-butene, 1-butene, isobutene, butadiene and acetylene. The process of recovering highly pure 1,3-butadiene includes acetylene conversion for selectively converting acetylene through liquid-phase hydrogenation, so that the acetylene content is decreased to 70 wt ppm or less, and 1,3-butadiene extraction using an extractive distillation column, a pre-separator, a solvent stripping column, a solvent recovery column, and a purification column. Through the acetylene conversion, the concentration of vinylacetylene is decreased to 70 wt ppm or less, after which 1,3-butadiene is recovered using only one extractive distillation column, thereby considerably decreasing the degree of utility and the loss of streams in the course of extraction. The number of units necessary for the process is decreased, thus remarkably reducing the time during which impurities can accumulate in a processing unit.