Parallel Flow Fractionation Tray with Inclined Downcomer Baffles
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Solution Overview
Problem
Existing vapor-liquid contacting trays face challenges in maximizing capacity and mass transfer efficiency, particularly in maintaining efficient flow and preventing flooding, with existing designs like Lewis' Case 2 parallel flow trays experiencing pinching and reduced active area due to stilling decks and imperforate regions.
Innovation Solution
The design incorporates multiple configurations of parallel flow multiple downcomer trays with central and side downcomers, inclined baffles, and bubble promoters to direct liquid flow and prevent pinching, including a central baffle that intersects contacting decks and side downcomers with receiving and distributing portions to enhance liquid distribution and vapor flow paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If stilling decks and imperforate regions are used in parallel flow trays, then liquid flow control is improved, but active area is reduced and pinching occurs
Solution Approach 1:
The tray is divided into multiple independent downcomer zones (central and side downcomers) with separate liquid flow paths. This segmentation allows liquid to be distributed through multiple channels, improving flow control without requiring large imperforate regions that would reduce active area. Each downcomer serves a specific zone, preventing pinching by distributing flow paths.
Solution Approach 2:
The invention introduces side downcomers positioned at the periphery of the tray, utilizing the radial dimension of the tray structure. This dimensional expansion allows liquid flow control to be achieved at multiple locations (center and periphery) simultaneously, improving overall flow distribution without blocking the central active area with a single large stilling deck.
2Productivity
If multiple downcomers are added to increase capacity, then tray capacity improves, but device complexity increases
Solution Approach 1:
Both central and side downcomers utilize the same basic structural design and liquid flow mechanism. This universal design approach allows multiple downcomers to be implemented without proportionally increasing complexity, as each unit serves the same function in a different location. The standardized configuration simplifies manufacturing and installation while increasing overall tray capacity.
3Stability of the object's composition
If liquid flow paths are extended to improve distribution, then liquid distribution uniformity improves, but pressure drop increases
Solution Approach 1:
The liquid flow path is segmented into multiple short paths through central and side downcomers rather than one long path. This segmentation reduces the cumulative pressure drop while maintaining distribution uniformity, as liquid travels shorter distances through each downcomer zone before entering the active area.
Solution Approach 2:
The invention provides liquid distribution through more downcomers than the minimum single central downcomer, creating excessive distribution points. This partial redundancy ensures uniform liquid distribution across the tray while keeping individual downcomer paths short, thereby limiting pressure drop accumulation.
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 increases tray capacity and efficiency by ensuring uniform liquid distribution, reducing pinching, and maintaining active area, thereby enhancing mass transfer and vapor-liquid contact, while maintaining structural integrity and operational flow.
Implementation Method 1
liquid flows in a generally horizontal direction across the device
Implementation Method 2
The inclined surface of the baffle also imparts a horizontal momentum to the descending liquid which tends to push the liquid and froth present on the tray towards the inlet of the outlet downcomer
Implementation Method 3
The cross flow of vapor and liquid streams on each device generates a froth for intimate vapor-liquid contacting and mass transfer
Implementation Method 4
intimate vapor-liquid contacting and mass transfer
Implementation Method 5
A bubble promoter, which comprises a perforated plate, is situated on the tray to direct liquid from the inclined downcomer baffle to one of the contacting decks
Implementation Method 6
vapor rises vertically through the column
Implementation Method 7
separation of chemical compounds via fractional distillation
Data Source
Figure 1
Figure 2~3
Figure 4A~5
AI summary
The invention comprises multiple configurations of downcomers (20) in a parallel flow multiple downcomer tray (100) for vapor-liquid contacting processes such as the separation of chemical compounds via fractional distillation or the removal of a component of a gas stream with a treating liquid. In one embodiment, side downcomers (104) are incorporated into a parallel flow multiple downcomer tray (100). In another embodiment, the downcomers (202) have an inclined side wall (220) that directs liquid onto the deck (206) below the downcomer. The inclined side wall (220) also provides additional volume above the inferior downcomer inlet to reduce pinching at this inlet without the need for a stilling deck (114).