Heat Exchanger Plate Flow Ridges for Desalination Separation

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Solution Overview

Problem

In seawater desalination processes using plate heat exchangers, the distribution of vaporized feed to the separation section and the separation of non-vaporized feed to the brine section are inefficient, leading to suboptimal utilization of the separation section and potential re-contamination of the evaporation section, which affects the quality of the condensed fresh water.

Innovation Solution

The use of elongated ridges on the heat exchanger plates as flow guiding elements, extending obliquely between the evaporation, separation, and brine sections, directs vaporized feed towards the center of the separation section and non-vaporized feed towards the brine section, eliminating the need for rubber gaskets and enhancing the utilization of the separation section.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If vaporized feed flows from evaporation section to separation section, then the separation process occurs, but the vaporized feed is not properly distributed over the complete evaporation section leading to unused central region of separator

Engineering Contradiction:
Improveutilization of separation sectionVSAvoidflow distribution
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The separation section is divided into multiple zones with different flow guiding elements (ridges and valleys) that segment the flow path. This segmentation directs vaporized feed from edge regions toward the central region, ensuring complete utilization of the separation section surface area and improving separation efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces three-dimensional flow guiding elements (ridges and valleys) on the plate surface to control two-dimensional flow distribution. These elements create vertical obstacles that redirect horizontal flow, transforming edge-parallel flow into radially distributed flow across the separation section.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If non-vaporized feed is not directed to brine section, then separation occurs, but droplets flow back to evaporation section increasing feed concentration

Engineering Contradiction:
Improveprevention of re-contaminationVSAvoidflow control structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The plate structure is segmented into distinct functional zones (evaporation section, separation section, brine section) separated by flow guiding elements. This segmentation creates automatic flow direction where non-vaporized feed droplets are channeled into brine sections by the ridge-valley structure, preventing backflow to the evaporation section and maintaining feed quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flow guiding elements (ridges and valleys) act as intermediary structures between the separation section and brine section. These intermediaries capture and redirect non-vaporized feed droplets before they can return to the evaporation section, serving as a barrier that maintains the integrity of the evaporation zone.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If rubber barrier is used for directing flow, then flow direction is controlled, but gasket handling and assembly becomes difficult and sensitive

Engineering Contradiction:
Improveflow direction controlVSAvoidgasket assembly
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent extracts the flow guiding function from the rubber gasket system and integrates it directly into the rigid plate structure through molded-in ridges and valleys. This extraction eliminates the need for separate rubber flow-directing barriers, simplifying gasket handling and assembly while maintaining effective flow control.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The flow guiding elements are merged with the plate body as an integrated structure rather than separate components. The ridges and valleys are molded directly into the plate during manufacturing, combining the structural and flow control functions into a single element, thereby eliminating assembly complexity associated with separate gasket systems.

Inventive Principle:
Principle #5Merging (Combining)

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 solution improves the distribution and separation efficiency, ensuring better utilization of the separation section and preventing non-vaporized feed from returning to the evaporation section, thereby enhancing the quality of the condensed fresh water and simplifying the assembly process by avoiding the use of rubber gaskets.

Implementation Method 1

each plate comprising a pair of front surface flow guiding elements for directing the vaporized feed towards the central axis

Methodology Applied
Scientific EffectFlow guidance:

Implementation Method 2

for directing the non-vaporized feed towards the respective brine section

Methodology Applied
Scientific EffectFlow guidance:

Implementation Method 3

an evaporation section on the front surface for vaporizing the liquid feed

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 4

a separation section on the front surface for separating vaporized feed and non-vaporized feed

Methodology Applied
Scientific EffectGravity separation: Gravitation

Implementation Method 5

a condensation section for condensing the vaporized feed

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 6

The heating section is heating the evaporation section

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 7

the cooling section is cooling the condensation section

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3792581B1Plate heat exchanger for treatment of a liquid feed
Publication Date: 2023.02.22 ALFA LAVAL CORP AB
  • EP3792581B1 patent drawingFigure 1
  • EP3792581B1 patent drawingFigure 2~3
  • EP3792581B1 patent drawingFigure 4~5

AI summary

The present invention relates to a heat exchanger plate for a plate heat exchanger for treatment of a liquid feed, the heat exchanger plate defines an evaporation section on the front surface for vaporizing the liquid feed, a separation section on the front surface for separating vaporized feed and non-vaporized feed, and a first- and second brine section on the front surface for receiving the non-vaporized feed. The separation sections being located between the evaporation section and the condensation section in the longitudinal direction, the first brine section being located between the evaporation section and the first longitudinal edge and the second brine section being located between the evaporation section and the second longitudinal edge. Each plate comprising a pair of front surface flow guiding elements for directing the vaporized feed towards the central axis and/or for directing the non-vaporized feed towards the respective brine section.