Annular divided wall column for an air separation unit having a ring shaped support grid
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Solution Overview
Problem
Existing annular divided wall columns for cryogenic rectification of air face challenges such as maldistribution of vapor and liquids, lower performance due to thermal expansion/contraction differences, and inadequate pressure boundaries, leading to increased capital costs and space requirements.
Innovation Solution
An annular divided wall column design featuring concentric annular column walls with a ring-shaped support grid allowing independent thermal expansion and contraction, and structured packing elements within the annulus and core column regions, along with specialized collectors and distributors to ensure uniform flow distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If divided-wall columns are used to reduce capital cost and space requirements, then column cost and space are reduced, but maldistribution of vapor and liquids occurs due to large wall surface areas
Solution Approach 1:
The support grid is segmented into multiple discrete support structures rather than a continuous wall, allowing vapor and liquid to distribute more uniformly across the column sections while maintaining structural support. This segmentation reduces the continuous wall surface area that causes maldistribution.
Solution Approach 2:
The support grid provides localized support at specific points rather than continuous wall support, creating optimal local conditions for vapor and liquid flow distribution. The discrete support structures are positioned to maintain proper flow patterns in critical areas without creating the maldistribution issues of continuous walls.
2Ease of manufacture
If divided-wall columns are used to reduce capital cost and space requirements, then column cost and space are reduced, but performance decreases due to thermal expansion/contraction differences between inner and outer shells
Solution Approach 1:
The second annular column wall is extracted from the rigid fixed structure and allowed to move independently. The support grid is designed to accommodate the thermal expansion and contraction of the column walls by providing flexible support points that do not constrain thermal movement, thereby preventing performance degradation from thermal stress.
Solution Approach 2:
The support grid system transitions from a static rigid structure to a dynamic system that accommodates thermal movement. The discrete support structures allow for controlled movement and expansion/contraction of the column walls while maintaining operational integrity throughout temperature cycles.
3Ease of manufacture
If divided-wall columns are used to reduce capital cost and space requirements, then column cost and space are reduced, but pressure boundary adequacy is compromised between interior core and annulus regions
Solution Approach 1:
The pressure boundary is segmented into discrete support structures rather than continuous walls. These segmented supports are strategically positioned to maintain adequate pressure containment between the interior core and annulus regions while using less material than continuous walls, thereby reducing cost while maintaining strength.
Solution Approach 2:
The support grid utilizes composite structural design combining different material properties to achieve adequate pressure boundary strength with reduced material usage. The discrete support structures are designed with optimized material selection and geometry to provide necessary pressure containment at lower cost.
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 design enhances performance by reducing capital costs and space requirements, improving vapor and liquid distribution, and maintaining efficient operation despite thermal expansion differences, thereby optimizing the cryogenic rectification process.
Implementation Method 1
thermal expansion and contraction of the second annular column wall in a radial direction and in an axial direction is independent of the thermal expansion and contraction of the ring-shaped support grid and the first annular column wall in the radial and axial directions
Implementation Method 2
a plurality of structured packing elements disposed on the ring-shaped support grid within the annulus column region
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 to define an annulus column region and an interior core column region. The present annular divided wall column further includes structured packing elements disposed within at least the annulus column region as well as a ring-shaped cantilevered collector; and a ring-shaped distributor disposed in the annulus column region above or below the plurality of structured packing elements. The thermal expansion and contraction of the second annular column wall in a radial direction and in an axial direction is independent of the thermal expansion and contraction of the first annular column wall in the radial and axial directions.