Dephlegmator Header Phase Separation Against Liquid Entrainment

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Solution Overview

Problem

Reflux condensers face inefficiencies in heat and mass transfer processes due to liquid entrainment by steam flows, leading to suboptimal separation and increased operational costs.

Innovation Solution

The integration of a phase separation device in the header at the lower end of the return passages within the reflux condenser, which separates vapor and liquid effectively, preventing liquid entrainment and allowing for enhanced heat and mass transfer efficiency, while also enabling the use of the pressure vessel space for other purposes and potentially different pressures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the return passages are open to the space between the pressure vessel and the heat exchanger core, then the structure is simpler, but liquid entrainment occurs and heat and mass transfer effectiveness decreases

Engineering Contradiction:
Improvestructural complexityVSAvoidheat and mass transfer effectiveness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The return passages are segmented from the pressure vessel interior space by introducing a header structure. This segmentation allows the return passages to have a dedicated enclosed space with controlled pressure, separate from the pressure vessel interior, thereby preventing liquid entrainment while maintaining structural organization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A header is introduced as an intermediary component between the return passages and the pressure vessel. The header serves as a mediator that provides a dedicated space for the return passages, enabling effective phase separation and preventing liquid entrainment by steam flow, thus improving heat and mass transfer effectiveness.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a phase separation device is added to the header, then liquid entrainment is prevented and separation efficiency improves, but device complexity increases

Engineering Contradiction:
Improveseparation efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The phase separation device is merged with the header structure, integrating the separation function directly into the existing header component. This combination allows effective phase separation to be achieved without adding a completely separate device, thereby improving separation efficiency while limiting the increase in overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If the pressure vessel interior space is used for other purposes with different pressure, then space utilization improves and operational flexibility increases, but the structure becomes more complex

Engineering Contradiction:
Improveoperational flexibilityVSAvoidstructural complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The pressure vessel interior space is designed to serve multiple functions: it can accommodate the heat exchanger core and simultaneously provide a separate pressurized environment for the return passages. This multi-functionality allows the space to be utilized for different purposes with different pressure conditions, improving operational flexibility while maintaining a unified structural design.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 significantly enhances the effectiveness of the heat and mass transfer process, prevents liquid entrainment, and allows for the efficient use of the pressure vessel space, resulting in improved operational economics and separation efficiency.

Implementation Method 1

a phase separation device can be arranged in the header, which makes it possible for vapor and liquid to be effectively separated from one another below the return passages

Methodology Applied
Scientific EffectPhase separation: Two-Phase Flow

Implementation Method 2

The heat exchanger block is preferably manufactured as a plate heat exchanger, in particular as a brazed aluminum plate heat exchanger

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

The return passages of a recycle condenser are subjected to steam from below. This partially condenses as it rises in the return passages

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 4

The liquid refrigerant is introduced via a socket (4) into the intermediate space (3) between the pressure vessel (2) and the heat exchanger block (1), where it forms a liquid bath

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 5

the gas passage opening is provided on its upper side with a border for damming up liquid. The vapor that rises and later enters the return passages flows past the accumulated liquid via the gas passage opening without suffering any significant pressure loss and without entraining liquid droplets. The border prevents liquid from flowing into the gas passage opening

Methodology Applied
Scientific EffectSurface tension barrier: Surface Tension

Data Source

PatentEP1890100B1Dephlegmator
Publication Date: 2018.06.13 LINDE AG
  • EP1890100B1 patent drawingFigure 1~2
  • EP1890100B1 patent drawingFigure 3~4
  • EP1890100B1 patent drawingFigure 5~7

AI summary

A return condenser comprises at least one heat exchanger block (1) having return passages and refrigerant passages, and a pressure vessel (2) that surrounds the heat exchanger block (1) at the top and sides. Means (14, 15, 16, 17) are provided for introducing steam into the lower part of the return passages, means (19) for removing liquid from the lower part of the return passages, means (29, 30) for extracting steam from the upper part of the return passages, and means for introducing refrigerant into the refrigerant passages. The return passages communicate at their lower end with a header located below the heat exchanger block (1) which includes a phase separation device.