Prefractionation Column for Heavy Aromatic Removal
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Solution Overview
Problem
Current processes for removing heavy aromatics from spent regenerant streams in linear alkylbenzene production are inefficient, requiring large hot oil duty and resulting in unreasonable product splits and column design issues.
Innovation Solution
The process involves introducing the spent regenerant stream to a prefractionation column, where it is separated to produce an overhead stream rich in regenerant and a bottoms stream rich in heavy aromatics, with a low temperature fluid stream used for vaporization to reduce hot oil duty and optimize product separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a desorbent column is used to remove heavy aromatics from spent regenerant stream, then heavy aromatics are removed, but large hot oil duty is required and product split becomes unreasonable
Solution Approach 1:
The separation process is divided into two distinct columns: a prefractionation column for initial separation of heavy aromatics, and a desorbent column for final purification. This segmentation allows each column to operate under optimized conditions, reducing the energy duty required in the desorbent column while maintaining effective heavy aromatic removal.
Solution Approach 2:
The prefractionation column performs preliminary separation of heavy aromatics from the spent regenerant stream before the material enters the desorbent column. This preliminary action reduces the load on the desorbent column, thereby reducing the hot oil duty required for vaporization and improving overall energy efficiency.
2Reliability
If a desorbent column is used to remove heavy aromatics from spent regenerant stream, then heavy aromatics are removed, but column design issues arise due to unreasonable product split
Solution Approach 1:
By segmenting the separation process into two columns with different functions, the invention eliminates the design complications that would arise from attempting to achieve both separation and purification in a single column. The prefractionation column handles bulk separation, while the desorbent column handles final purification, resulting in more reasonable product splits and simplified column design.
3Reliability
If conventional single-column process is used, then heavy aromatics are removed, but energy consumption increases and product distribution becomes unreasonable
Solution Approach 1:
The process is segmented into two columns where the prefractionation column performs initial separation and the desorbent column performs final purification. This segmentation reduces the energy consumption in the desorbent column by reducing the amount of material requiring high-temperature vaporization, thereby reducing overall hot oil duty while maintaining effective heavy aromatic removal.
Solution Approach 2:
The prefractionation column performs preliminary separation that reduces the burden on the desorbent column. By removing the bulk of heavy aromatics in the prefractionation column, the desorbent column requires less energy for vaporization, thus reducing overall energy loss while achieving complete separation.
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 hot oil duty and improves product split, allowing for more efficient separation of heavy aromatics, resulting in a smaller desorbent column with a more reasonable product distribution.
Implementation Method 1
introducing a feed stream comprising the second component and less than about 5 wt % of the first component to one or more top trays of a prefractionation column. The feed stream is separated in the prefractionation column to provide a prefractionation column overhead stream comprising at least about 50 wt % of the second component
Implementation Method 2
A first portion of the prefractionation columns bottom stream is vaporized by heat exchange with a low temperature fluid stream having a temperature of about 150-200° C. in a reboiler
Implementation Method 3
A second portion of the prefractionation column bottoms stream is separated in a fractionation column to provide a fractionation column overhead stream rich in the second component and a fractionation column bottoms stream rich in the first component
Data Source
AI summary
Processes for removal of heavy aromatic compounds in an alkylated aromatic compounds production complex is disclosed. The processes includes separating a first component from a second component comprising introducing a feed stream comprising the second component and less than about 5 wt % of the first component to one or more top trays of a prefractionation column. The feed stream is separated in the prefractionation column to provide a prefractionation column overhead stream comprising at least about 50 wt % of the second component present in the feed stream and a prefractionation column bottoms stream. A first portion of the prefractionation columns bottom stream is vaporized by heat exchange with a low temperature fluid stream having a temperature of about 150-200° C. in a reboiler and passing the vaporized first portion through the prefractionation column.