Multiple pass, parallel flow downcomer tray for a mass transfer column
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional mass transfer columns face limitations in high-capacity vapor-liquid contacting due to restricted active area and downcomer configuration, leading to inefficiencies in mass transfer, particularly in high-pressure distillation systems.
Innovation Solution
A parallel flow, multiple pass downcomer tray design featuring an annular tray with multiple mass transfer decks, central and peripheral downcomers, ramp-like channels, liquid receiving pans, bubble forming structures, and perforated plates to ensure uniform liquid distribution and prevent vortex flow, enhancing mass transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional single pass or two pass downcomer configurations are used, then the tray structure is simple, but the liquid handling capability is insufficient for high liquid rate distillation systems
Solution Approach 1:
The downcomer system is segmented into multiple independent downcomers (first downcomer, second downcomer, third downcomer) distributed across the tray. Each downcomer handles a portion of the liquid flow, collectively providing high liquid rate handling capability while maintaining manageable individual component complexity
Solution Approach 2:
Different regions of the tray are assigned different downcomer locations and characteristics. The first downcomer is positioned at a first location, the second downcomer at a second location, and the third downcomer at a third location, optimizing local liquid flow distribution and handling characteristics for high liquid rate conditions
2Productivity
If large downcomer area is provided to increase liquid handling capability, then the liquid discharge capacity increases, but the active area for vapor-liquid contacting is reduced
Solution Approach 1:
The total downcomer area is segmented into multiple smaller downcomers distributed across the tray rather than one large downcomer. This segmentation allows the liquid discharge capacity to be distributed across multiple locations, reducing the impact on any single region's active area while maintaining overall high liquid handling capability
Solution Approach 2:
Instead of concentrating liquid discharge capacity in a single large area, the system distributes discharge capacity across multiple spatial dimensions by placing multiple downcomers at different locations (first location, second location, third location), effectively utilizing the tray's planar dimensions to balance active area and discharge capacity
3Productivity
If liquid flow rate is increased to handle high liquid rates, then the liquid handling capability increases, but vapor maldistribution and flooding occur
Solution Approach 1:
The liquid flow is segmented into multiple streams by distributing it across multiple downcomers at different locations. This segmentation prevents any single region from experiencing excessive liquid flow rates that would cause flooding or vapor maldistribution, while collectively handling high overall liquid rates
Solution Approach 2:
Each downcomer location is optimized for its local conditions, with the first downcomer at a first location, second downcomer at a second location, and third downcomer at a third location. This local optimization ensures that each region handles liquid flow at appropriate rates, preventing localized flooding and maintaining vapor-liquid contacting efficiency
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
The design improves mass transfer efficiency by maintaining uniform driving forces across trays, reducing weir loading, and minimizing vapor maldistribution, thereby increasing the overall capacity and performance of mass transfer columns.
Implementation Method 1
The one or more perforated plates are configured to provide uniform distribution of the liquid from the liquid receiving pans to the mass transfer areas and avoid formation of the vortex type flow arrangement on the mass transfer decks
Implementation Method 2
one or more bubble forming structures disposed on the tray surface between the liquid receiving pans and plurality of mass transfer decks
Implementation Method 3
one or more ramp-like peripheral channels and one or more peripheral liquid receiving pans disposed on the tray surface, the ramp-like peripheral channels configured to direct descending liquid received by the one or more ramp-like peripheral channels to the one or more peripheral liquid receiving pans
Implementation Method 4
each mass transfer deck being disposed adjacent to at least two other mass transfer decks and configured to provide contact between an ascending vapor passing through the apertures and a traversing liquid on the tray surface
Data Source
AI summary
A multiple pass, parallel flow downcomer tray for a mass transfer column and method for liquid-vapor contacting in a mass transfer column is provided. The multiple pass, parallel flow downcomer tray has at least four mass transfer decks configured to provide contact between an ascending vapor passing upward through apertures on the tray surface and a traversing liquid on the tray surface. The tray further includes a central downcomers disposed near a central axis of the tray and two or more peripheral downcomers disposed near the edge of the tray and spaced apart from the central axis, wherein at least two of the four mass transfer decks are configured to discharge the traversing liquid into the peripheral downcomers and two of the four mass transfer decks are configured to discharge the traversing liquid into the central downcomer.