Annular Divided Wall Column Layout for Flow Distribution in Air Separation
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Solution Overview
Problem
Conventional annular divided wall columns for cryogenic distillation of air face challenges with high capital costs and space requirements due to maldistribution of vapor and liquid in separation sections, especially when using structured packing as mass-transfer elements.
Innovation Solution
The design incorporates a first and second annular column wall with a defined annulus and interior core column region, each containing structured packing elements of different densities and geometries to optimize mass transfer efficiency and reduce costs and space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional annular divided wall columns use structured packing as mass-transfer elements, then mass transfer efficiency is improved, but vapor and liquid maldistribution occurs leading to reduced separation performance
Solution Approach 1:
The patent applies local quality by using different packing types in different regions: structured packing in the inner column for high mass transfer efficiency, and random packing in the outer annular column for better flow distribution. This regional differentiation resolves the contradiction by optimizing each zone for its specific function.
Solution Approach 2:
The column is segmented into two distinct packing zones (inner and outer columns) with different packing characteristics. This segmentation allows each zone to perform optimally without the maldistribution problems that would occur if a single packing type were used throughout.
2Productivity
If multi-column systems are used for cryogenic rectification of air, then separation capability is improved, but capital cost and space requirements increase
Solution Approach 1:
The patent merges multiple separation functions into a single divided wall column structure. The inner and outer columns operate simultaneously within one shell, combining the separation capabilities of what would traditionally require multiple separate columns, thereby reducing space requirements and capital cost.
Solution Approach 2:
The inner column is nested within the outer annular column, creating a compact configuration that achieves multi-stream separation in a reduced footprint. This nesting arrangement allows two independent separation sections to coexist in the space of approximately one conventional column.
3Strength
If annular divided wall columns are designed with large wall surface area, then structural integrity is improved, but liquid maldistribution worsens
Solution Approach 1:
The patent addresses liquid distribution by using random packing in the outer column region where liquid flows downward, as random packing provides better liquid redistribution characteristics compared to structured packing. This local optimization maintains structural integrity while improving liquid distribution in the critical liquid flow zone.
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 enhances the performance of air separation by minimizing maldistribution and reducing capital costs and space needs, achieving more efficient cryogenic rectification of air and its constituents.
Implementation Method 1
a plurality of packing elements or trays disposed within the interior core column region and the annulus column region
Implementation Method 2
The present invention relates to annular divided wall columns for the cryogenic distillation of air or constituents of air
Data Source
AI summary
An annular divided wall column for the cryogenic rectification of air or constituents of air is provided. The annular divided wall column includes a first annular column wall and a second annular column wall disposed within the first annular column wall and radially spaced therefrom to define an annulus column region as the space between the first annular column wall and the second annular column wall. An interior core column region is also defined by the interior space of the second annular column wall. The present annular divided wall column further includes a plurality of packing elements, plurality of trays or a heat exchange device disposed within the interior core column region; and a plurality of packing elements disposed within the annulus column region.