De-entrainment Device for Distillation Columns

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Solution Overview

Problem

In vapor-liquid contacting devices, particularly in high capacity distillation columns, the entrainment of liquid in vapor streams leads to reduced capacity and efficiency due to compositional mismatch and increased liquid traffic, which complicates effective separation, especially in sections near reboiler returns or feed introductions.

Innovation Solution

The implementation of de-entrainment devices with modular construction, featuring non-parallel alignment and bypass conduits that direct liquid from downcomers to avoid co-current flow channels, allowing efficient separation of entrained liquid from vapor, thus maintaining high capacity and efficiency while minimizing pressure drop.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional fractionation trays are used for high capacity vapor-liquid contacting, then vapor and liquid handling capacity is increased, but liquid entrainment in vapor streams increases causing compositional mismatch and reduced efficiency

Engineering Contradiction:

Improvevapor and liquid handling capacityVSAvoidseparation efficiency

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The tray is divided into multiple functional zones: a high-capacity contacting section for vapor-liquid mass transfer, and a separate de-entrainment section with coalescing elements. This segmentation allows the tray to simultaneously handle high vapor/liquid traffic while effectively separating entrained liquid from vapor streams through the dedicated de-entrainment zone.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The de-entrainment function is extracted as a separate functional element within the tray structure. Coalescing elements are positioned in the vapor path to specifically address liquid entrainment removal, separating this function from the main contacting function and allowing optimized performance of both.

Inventive Principle:

Principle #2Taking out (Extraction)

2Productivity

If tray spacing is reduced to increase column capacity, then more trays can be installed, but vapor velocity increases causing greater liquid entrainment

Engineering Contradiction:

Improvecolumn capacityVSAvoidliquid entrainment

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

Coalescing elements serve as intermediary structures in the vapor path that capture and coalesce entrained liquid droplets. These elements provide a mechanism for liquid removal without requiring increased tray spacing, allowing high vapor velocities to be maintained while still achieving effective de-entrainment.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If de-entrainment devices are added to separate entrained liquid, then separation efficiency is improved, but device complexity and space requirements increase

Engineering Contradiction:

Improveseparation efficiencyVSAvoidtray structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The de-entrainment function is merged with the existing tray structure rather than being implemented as a separate device. Coalescing elements are integrated into the tray deck or positioned within the vapor path in a space-efficient manner, combining multiple functions (contacting, separation, and de-entrainment) in a single integrated structure.

Inventive Principle:

Principle #5Merging (Combining)

4Reliability

If conventional de-entrainment methods are used, then liquid separation is achieved, but pressure drop increases reducing overall column efficiency

Engineering Contradiction:

Improveliquid vapor separationVSAvoidpressure drop

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

Coalescing elements with porous or mesh structures are used to provide large surface area for liquid-vapor separation. These porous structures allow vapor to pass through with minimal resistance while effectively capturing and coalescing liquid droplets, achieving good separation efficiency with low pressure drop.

Inventive Principle:

Principle #31Porous materials

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 de-entrainment devices effectively separate entrained liquid from vapor streams, enhancing column performance by preventing compositional mismatch and maintaining high vapor and liquid handling capabilities with minimal space occupation.

Implementation Method 1

de-entrainment devices for separating liquid that is entrained in a vapor stream

Methodology Applied

Scientific EffectGravitational settling: Gravitation

Implementation Method 2

allowing efficient separation of entrained liquid from vapor

Methodology Applied

Scientific EffectCoalescence: Coagulation

Data Source

PatentEP2370204B1De-entrainment device

Publication Date: 2018.09.19 UOP LLC

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AI summary

De-entrainment devices for effectively removing entrained liquid from a vapor stream are disclosed. These de-entrainment devices are effective in distillation columns and other apparatuses comprising vapor-liquid contacting devices. Particular representative applications for these de-entrainment devices are in distillation (or fractionation) columns having co-current contacting modules, in which liquid and vapor enter into co-current flow channels of the modules. The de-entrainment devices can be used, for example, with non-parallel contacting stages or other types of high capacity trays.