Simulated Moving Bed Paraxylene Separation with Optimized Zone Configurations
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Solution Overview
Problem
Current Simulated Moving Bed (SMB) devices require a high number of adsorbent beds (typically 24) to achieve paraxylene purity of 99.7% or more, leading to complex and costly setups, whereas achieving high purity with a reduced number of beds has been considered impractical.
Innovation Solution
Implementing specific configurations of adsorbent beds and zones, such as (2, 5, 3, 2), (3, 6, 4, 2), or (4, 7, 6, 2), with desorbents like toluene or paradiethylbenzene, to achieve high paraxylene purity in a single stage with fewer adsorbent beds, reducing the complexity and cost of SMB devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a high number of adsorbent beds (typically 24) are used in SMB devices, then paraxylene purity of 99.7% or more is achieved, but device complexity and cost increase
Solution Approach 1:
The patent changes the operational parameters of the SMB device, specifically the flow rates and switching times in different zones, to optimize separation efficiency. By adjusting these parameters, the device achieves high paraxylene purity with fewer beds (12-16), resolving the contradiction between purity and device complexity
Solution Approach 2:
The patent applies different bed configurations to different zones within the SMB device. Specific zones have optimized numbers of beds based on their functional requirements, allowing high purity separation with a reduced total number of beds, thus reducing overall device complexity while maintaining manufacturing precision
2Manufacturing precision
If a high number of adsorbent beds (typically 24) are used in SMB devices, then paraxylene purity of 99.7% or more is achieved, but device cost increases
Solution Approach 1:
By optimizing operational parameters such as flow rates and switching times, the patent reduces the number of adsorbent beds required from 24 to 12-16 beds. This parameter optimization directly reduces material costs and manufacturing complexity, resolving the contradiction between achieving high purity and reducing device cost
Solution Approach 2:
The patent implements a reduced configuration of adsorbent beds (12-16 instead of 24) that provides sufficient separation capability for achieving high paraxylene purity. This partial action approach avoids the excessive investment in full 24-bed configurations while maintaining the required manufacturing precision
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 allows for the attainment of paraxylene purity exceeding 99.5% with fewer adsorbent beds, resulting in more economical and efficient SMB devices with superior performance levels, as demonstrated by specific bed configurations and desorbent selections.
Implementation Method 1
a family of adsorption processes and associated devices is then used, known under the name of processes or devices for 'chromatographic' separation or 'in a simulated moving bed'
Implementation Method 2
at least one feedstock F to be fractionated and one desorbent D (sometimes called eluant) are supplied
Data Source
AI summary
Process for separating paraxylene with a purity that is at least equal to 99.5% by weight from an aromatic feedstock F in a single adsorption stage in a simulated moving bed (SMB), comprising different numbers of beds, allocated to a zone 1 between the supply of the desorbent D and the draw-off of the extract E; a zone 2 between the draw-off of the extract E and the supply of the feedstock F; a zone 3 between the supply of the feedstock and the draw-off of the raffinate R; a zone 4 between the draw-off of the raffinate R and the supply of the desorbent D, wherein an SMB of 12 adsorbent beds has bed configuration (2, 5, 3, 2), an SMB of 15 adsorbent beds has bed configuration (3, 6, 4 , 2), or an SMB of 19 adsorbent beds has bed configuration (4, 7, 6, 2), wherein the desorbent in this latter case is paradiethylbenzene.