Dividing Wall Column Alkanolamine Separation
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Solution Overview
Problem
Conventional distillation columns with side draws are limited by the impurity of side products, which restricts their application to cases allowing contaminated fractions, and there is a need for an efficient process to separate mixtures of monoisopropanolamine (MIPOA), diisopropanolamine (DIPOA), and triisopropanolamine (TIPOA) in high purity.
Innovation Solution
The process involves a conventional distillation column followed by two dividing wall columns, where MIPOA is separated as a side draw from the first dividing wall column and DIPOA and TIPOA are obtained as side draws from the second, allowing for high-purity recovery of alkanolamines with low investment and energy costs, and optionally using thermal coupling of distillation columns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional distillation columns with side draws are used, then equipment expenditure is limited, but side products contain impurities that restrict application to cases allowing contaminated fractions
Solution Approach 1:
The distillation column is segmented into multiple sections by introducing dividing walls that create separate zones (rectification section, stripping section, and side draw section). This segmentation allows different components to be separated and drawn off at different locations, enabling high-purity side products while maintaining cost-effective equipment design.
Solution Approach 2:
Dividing walls act as intermediary structures that partition the column interior, creating separate flow paths for liquid and vapor streams. These dividing walls enable selective side draws of high-purity fractions without requiring multiple separate columns, thus resolving the contradiction between equipment cost and product purity.
2Manufacturing precision
If dividing wall columns are used to obtain high purity side products, then side product purity is improved, but device complexity increases
Solution Approach 1:
Multiple distillation functions are merged into a single column structure by incorporating dividing walls and side draw outlets. Instead of using separate columns for different separation tasks, the design combines rectification, stripping, and side draw operations in one integrated unit, reducing overall device complexity while maintaining high product purity.
Solution Approach 2:
The distillation column is designed with multi-functionality, serving as both a rectification column, a stripping column, and a side draw column simultaneously. The dividing walls and multiple outlets enable the same equipment to perform multiple separation functions, reducing the need for additional specialized equipment.
3Manufacturing precision
If multiple distillation columns are used to separate multi-component mixtures, then separation purity is improved, but equipment expenditure and device complexity increase
Solution Approach 1:
The separation task is segmented into different zones within a single column, with dividing walls creating distinct regions for different component separations. This allows multiple components to be separated at different locations in the same column, achieving high purity without requiring multiple separate columns.
Solution Approach 2:
The column design nests multiple separation functions within a single structural unit, where dividing walls and side draw outlets are integrated into the column body. This nested arrangement enables complex multi-component separation while maintaining a simple overall equipment footprint.
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 process achieves high-purity separation of MIPOA, DIPOA, and TIPOA with purity levels above 98% by weight, reducing energy consumption and investment costs while adhering to specified color quality standards.
Implementation Method 1
the continuous distillative separation of a mixture containing monoisopropanolamine (MIPOA), diisopropanolamine (DIPOA) and triisopropanolamine (TIPOA)
Implementation Method 2
MIPOA is separated off as a side draw stream from the longitudinally divided area
Implementation Method 3
a mixture containing DIPOA and TIPOA via the bottom, the latter being further processed in a second dividing wall column (TK 3), in which DIPOA is obtained as a side draw stream
Data Source
Figure 1
Figure 1a
Figure 1b
AI summary
The invention relates to devices and to a method for continuous distillative separation of a mixture containing one or more alkanolamine(s), wherein the separation is carried out in one or more dividing wall column(s) and wherein the alkanolamine or alkanolamines are withdrawn as a side extraction stream or side extraction streams (side fraction(s)).