Dividing Wall Distillation for Cumene Purification
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Solution Overview
Problem
The cumene purification process consumes a large amount of energy due to the use of supplementary devices like condensers and heat exchangers in existing distillation column configurations.
Innovation Solution
The use of a first and second dividing wall type distillation column, which separates benzene and cumene/polyisopropylbenzene streams in two steps, reducing the energy consumption by optimizing the flow ratio of benzene between the columns and recycling it back to reaction units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional distillation columns with supplementary devices (condensers, heat exchangers) are used for cumene purification, then purification function is achieved, but energy consumption increases
Solution Approach 1:
The patent combines multiple distillation functions into a single dividing wall distillation column. The column simultaneously performs benzene separation, cumene purification, and PIPB removal in one integrated structure, eliminating the need for multiple separate distillation columns and their associated supplementary devices like condensers and heat exchangers, thereby significantly reducing energy consumption
Solution Approach 2:
The dividing wall distillation column is segmented into multiple functional sections by internal dividing walls. These walls create separate zones within the single column that handle different separation tasks (benzene overhead, cumene side draw, PIPB bottom), allowing complex purification to be achieved through structured segmentation rather than multiple external units
2Manufacturing precision
If multiple separate distillation columns are used for stepwise separation of benzene, cumene, and PIPB, then separation precision is improved, but device complexity increases
Solution Approach 1:
The patent transitions from a horizontal arrangement of multiple separate columns to a vertical integrating wall structure within a single column. The dividing walls create three-dimensional flow paths that enable simultaneous multi-component separation, achieving the same separation precision as multiple columns but in a more compact, single-unit configuration
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 energy consumption by minimizing the load on each distillation column and enhancing energy efficiency in the cumene purification process.
Implementation Method 1
a first dividing wall type distillation column which takes in a stream from an alkylation reaction unit, and includes a first benzene out-put line through which benzene is discharged and a lower out-put line through which a benzene/cumene/polyisopropylbenzene (PIPB) stream is discharged
Implementation Method 2
a second dividing wall type distillation column which takes in a stream from a trans alkylation reaction unit and the benzene/cumene/PIPB stream discharged through the lower out-put line of the first dividing wall type distillation column, and includes a second benzene out-put line through which benzene is discharged from the upper portion, and a PIPB stream out-put line through which a PIPB stream is discharged from the lower portion
Data Source
AI summary
The present application relates to an apparatus for purifying cumene comprising: a first dividing wall type distillation column which takes in a stream from an alkylation reactor and comprises a first benzene output line and a benzene/cumene/polyisopropylbenzene stream output line; a second dividing wall type distillation column which takes in a stream from a transalkylation reactor and a benzene/cumene/polyisopropylbenzene stream, includes a transalkylation reactor stream input line, a benzene/cumene/polyisopropylbenzene stream input line, a second benzene output line, and a first polyisopropylbenzene stream output line; and a third distillation column which takes in a polyisopropylbenzene stream, includes a second polyisopropylbenzene output line, and a heavies output line.