Concentric Column Air Separation to Reduce Cold Box Footprint
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Solution Overview
Problem
Existing air separation systems require larger cold boxes due to the addition of additional columns, necessitating either an enlarged cold box or a separate one, which is inefficient in terms of space utilization and increases costs.
Innovation Solution
The use of concentric columns, where a third column is positioned concentrically around a first column, sharing a common wall, with minimal pressure and temperature differences to minimize heat transfer and reduce the need for additional space, allowing efficient operation without enlarging the cold box.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a third column is added to the air separation system, then the separation efficiency is improved, but the cross-sectional area of the cold box increases
Solution Approach 1:
The third column is nested concentrically within the second column, with the third column having a smaller diameter and being positioned inside the annular space between the first and second columns. This nesting arrangement allows the third column to share the cold box space with the other columns, thereby improving separation efficiency without increasing the overall cross-sectional area of the cold box
2Quantity of substance
If the third column is placed outside the existing column structure, then the separation capacity is improved, but the cold box size must be enlarged
Solution Approach 1:
Instead of adding the third column in the horizontal plane (which would increase cross-sectional area), the invention utilizes the vertical dimension by arranging the third column concentrically within the existing column structure. The third column is positioned at an intermediate height between the first and second columns, allowing it to operate at an intermediate pressure while sharing the same cold box volume
3Area of stationary object
If concentric columns are used to save space, then the cold box size is reduced, but heat transfer disturbances may occur
Solution Approach 1:
The concentric column arrangement is implemented with specific local considerations: the third column is positioned at an intermediate height rather than spanning the entire height, and the annular space between columns is designed to maintain proper thermal insulation. This localized application of concentric arrangement minimizes heat transfer disturbances while still achieving space savings
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 optimizes space usage, reduces construction costs, and maintains efficient distillation performance by minimizing thermal interference between columns, thus maintaining operational efficiency.
Implementation Method 1
Device and method for air separation by cryogenic distilling
Implementation Method 2
maintaining pressure differences and temperature differentials that prevent heat transfer disturbances
Data Source
Figure 1
AI summary
A cryogenic distillation air separation apparatus comprises three columns (K1, K2, K3), two of which are concentric (K1, K3), the external diameter of the third column (K3) being at most equal to that of the second column (K2), a line to supply the third column with air (AG), a reflux line (13) connected to an intermediate level of the upper section of the first column to draw off a nitrogen-enriched liquid, the line being connected to the head of the second column and passing through a region of the third column devoid of heat exchange means and mass exchange means, and an intermediate line (LPI) to draw off a liquid at an intermediate level of the first column.