Inverted Aromatic Distillation for Energy Reduction
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Solution Overview
Problem
Current methods for separating benzene, toluene, and C8+ compounds in aromatic complexes are energy-intensive, requiring significant fuel and electricity consumption.
Innovation Solution
A process and device configuration that includes a reformate column, aromatics extraction unit, and transalkylation unit, with specific feeding and separation strategies in distillation columns to optimize energy efficiency, such as reversing the order of benzene and toluene columns and introducing feeds separately, to reduce energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional distillation column configuration is used for separating benzene, toluene and C8+ compounds, then separation effectiveness is maintained, but energy consumption is high
Solution Approach 1:
The patent inverts the traditional sequence of distillation columns by placing the toluene column before the benzene column. This reversal allows the toluene column to operate at higher temperatures and pressures, generating steam that can be used to drive the benzene column, thereby reducing overall energy consumption while maintaining separation effectiveness.
Solution Approach 2:
The patent changes operating parameters (temperature, pressure) across different columns in the inverted sequence. The toluene column operates at higher T&P conditions to generate process steam, while the benzene column operates at lower conditions using this generated steam, optimizing energy utilization throughout the system.
2Use of energy by moving object
If separate feeding of toluene column from aromatics extraction unit and stabilization column is implemented, then energy consumption is reduced, but device complexity increases
Solution Approach 1:
The patent segments the feeding of the toluene column into two separate streams: one from the aromatics extraction unit and another from the stabilization column. This segmentation allows each feed to be optimized independently for energy efficiency, with the combined feeds entering at different points in the column to maximize heat integration and reduce reboiler energy consumption.
3Manufacturing precision
If toluene column is fed with C7+ cut from stabilization column bottom, then separation efficiency improves, but energy consumption increases
Solution Approach 1:
The patent performs preliminary separation in the toluene column by feeding it with the C7+ cut from the stabilization column bottom. This preliminary action removes heavier components before the material enters the benzene column, improving overall separation efficiency. The inverted sequence allows this energy-intensive step to be performed when the column can operate at optimal conditions for handling heavier fractions.
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 configuration achieves a significant energy gain, reducing reboiler energy consumption by over 10% compared to traditional methods, while maintaining effective separation of benzene, toluene, and C8+ compounds.
Implementation Method 1
separation by distillation between benzene, toluene and heavier compounds with 8 or more carbon atoms
Implementation Method 2
overhead product from the toluene column enriched in benzene and toluene
Implementation Method 3
bottom product from the toluene column enriched in compounds with 8 or more carbon atoms
Implementation Method 4
aromatics extraction unit
Implementation Method 5
transalkylation unit
Data Source
Figure 1
Figure 2
AI summary
The present invention relates to a method and device for separating a feed comprising benzene, toluene and C8+ compounds, in which: a toluene column (C10) is directly fed with a C7+ cut from the bottom of a stabilization column (C11) located downstream of a transalkylation unit (P4); a C7- cut is withdrawn from the top of the toluene column (C10) and a C8+ cut from the bottom; a benzene column (C9) is fed with the C7- cut from the toluene column (C10); an essentially aromatic cut from an aromatic extraction unit (P1) is injected into the toluene column (C10) separately above the feed of the C7+ cut or into the benzene column (C9).