Perforated-Tray Column With Segmented Downcomer Pipes
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Solution Overview
Problem
Perforated-tray columns face challenges in maximizing the active area for liquid-vapor interaction due to the presence of large downcomer inlet and outlet areas, which reduce the available active area and lead to suboptimal fluid dynamics, particularly resulting in cross-flow regimes that are not efficient for mass transfer.
Innovation Solution
The implementation of a perforated tray column design featuring multiple vertically aligned downcomer pipes that eliminate the need for downcomer inlet areas on each tray, allowing liquid to be distributed uniformly across the tray surface through multiple transfer points, promoting turbulent flow and increasing the active area, with downcomer pipes arranged in a pattern that facilitates radial liquid flow without preferred directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single downcomer is used for each tray, then the liquid can be conveyed to the next tray, but the downcomer inlet area and outlet area reduce the available active area significantly
Solution Approach 1:
The single downcomer is segmented into multiple downcomers distributed across the tray. This segmentation eliminates the need for large downcomer inlet and outlet areas, thereby increasing the active area available for liquid-vapor contact while maintaining the liquid conveyance function.
Solution Approach 2:
The downcomers are arranged in a vertical stack configuration, utilizing the vertical dimension to convey liquid between trays. This dimensional approach allows liquid to be distributed at multiple heights, eliminating the need for horizontal downcomer inlet/outlet areas and maximizing the active area.
2Quantity of substance
If large downcomers are used to convey liquid, then the liquid flow capacity is sufficient, but the fluid dynamics become suboptimal and the active area is reduced
Solution Approach 1:
The liquid flow capacity previously handled by a single large downcomer is segmented across multiple smaller downcomers. This segmentation maintains the total liquid conveyance capacity while eliminating the need for large downcomer inlet/outlet areas, thereby increasing the active area.
3Productivity
If cross-flow regime is used for liquid-gas interaction, then the liquid flows from input side to output side, but the mass transfer efficiency is suboptimal
Solution Approach 1:
Instead of using cross-flow where liquid and gas move perpendicular to each other, the invention inverts the approach by using counter-current flow where liquid flows downward and gas flows upward through the same vertical path. This inversion maximizes the interaction time and mass transfer efficiency between the two phases.
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 the active area, improves liquid-gas interaction, and increases the efficiency of heat and mass transfer by distributing liquid uniformly and reducing the need for baffles, resulting in a more efficient counter-current flow regime.
Implementation Method 1
The liquid is transferred form one tray to another via a plurality of downcomer pipes... each downcomer pipe has an upper inlet section, extending above the tray, and a lower outlet section extending towards the next tray
Implementation Method 2
The space inside the column is partitioned by a perforated tray assembly to facilitate interaction between two process streams, typically between a downwardly flowing liquid and an ascending gas or vapor. Particularly, the perforated trays enhance heat exchange and mass transfer between the process streams
Implementation Method 3
The perforated trays enhance heat exchange and mass transfer between the process streams
Implementation Method 4
allowing liquid to be distributed uniformly across the tray surface through multiple transfer points, promoting turbulent flow
Data Source
Figure 1~3
Figure 4a~4b
AI summary
A perforated-tray column wherein each tray comprises downcomer pipes (6) for conveying a downwardly flowing liquid (L) to a next tray, wherein the downcomer pipe includes: a first portion (7) extending above the perforated tray, a second portion (8) extending below the perforated tray towards the next perforated tray, and an end guard (9) to prevent a gasous phase from entering the downward pipe.