Ice-Brine Separation via Density-Gradient Flotation Medium

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Solution Overview

Problem

The freezing process for desalination has been hindered by the difficulty in separating ice from brine, leading to inefficient large-scale operation and high maintenance, which has deterred its adoption beyond small units.

Innovation Solution

The use of a liquid flotation medium with a specific gravity higher than ice but lower than the brine allows for the separation of ice from brine by flotation, forming a slurry that facilitates easy separation, transport, and recovery of purified water.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If freezing process is used for desalination, then energy consumption is reduced, but separation of ice from brine becomes difficult

Engineering Contradiction:
Improveenergy consumptionVSAvoidseparation of ice from brine
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

A hydrophobic coating is applied to the freezing surface to act as an intermediary layer that prevents brine from adhering to the ice. This coating allows ice to form and detach easily, solving the separation difficulty while maintaining the low energy consumption advantage of freezing

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The surface properties of the freezing surface are changed by applying a hydrophobic coating, which alters the interaction between ice and brine. This parameter change enables easy separation of ice from brine without requiring additional energy input

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If freezing process is used for desalination, then corrosion is reduced, but ice separation and harvesting becomes problematic

Engineering Contradiction:
ImprovecorrosionVSAvoidice separation and harvesting
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The hydrophobic coating serves as a mediator between the freezing surface and the ice-brine mixture, enabling easy ice harvesting while maintaining the corrosion-resistant properties of the freezing surface

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mechanical difficulty of ice harvesting is replaced by a chemical/surface property solution (hydrophobic coating), which causes ice to naturally detach without requiring complex mechanical harvesting systems

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Use of energy by moving object

If reverse osmosis is used for desalination, then power consumption is reduced, but environmental impact and maintenance increase

Engineering Contradiction:
Improvepower consumptionVSAvoidenvironmental impact and maintenance
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The process uses phase transition (freezing) instead of pressure-driven membrane filtration, eliminating the environmental and maintenance issues associated with RO membranes while achieving comparable or lower power consumption

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The mechanical membrane system of RO is replaced with a thermal phase change system, which has no moving parts or consumable components, thereby eliminating maintenance requirements and environmental impact from membrane disposal

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 method enables efficient separation of ice from brine, reducing the amount of occluded brine and achieving high water recovery rates, potentially making the freezing process a viable option for large-scale desalination with lower energy consumption and maintenance costs.

Implementation Method 1

The use of a liquid flotation medium with a specific gravity higher than ice but lower than the brine allows for the separation of ice from brine by flotation

Methodology Applied
Scientific EffectFlotation: Froth Floatation

Implementation Method 2

the flotation medium has a density greater than or equal to the density of ice or hydrate and less than the density of the aqueous mixture or a concentrated brine

Methodology Applied
Scientific EffectDensity difference: Density Gradient

Implementation Method 3

reducing the temperature of the aqueous mixture to a temperature ranging between the freezing point of the aqueous mixture and the eutectic temperature of the aqueous mixture to form ice or hydrate

Methodology Applied
Scientific EffectFreezing: Freezing

Implementation Method 4

reducing the temperature of the aqueous mixture to a temperature ranging between the freezing point of the aqueous mixture and the eutectic temperature of the aqueous mixture to form ice or hydrate

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP2663529B1Process and apparatus for water purification
Publication Date: 2020.03.18 CRYODESALINATION LLC
  • EP2663529B1 patent drawingFigure 1A~1B
  • EP2663529B1 patent drawingFigure 1C~1D
  • EP2663529B1 patent drawingFigure 1E~1F

AI summary

A process for purifying water via freezing is disclosed. The process may include: contacting an aqueous mixture with a flotation medium, wherein the flotation medium has a density greater than or equal to the density of ice or hydrate and less than the density of the aqueous mixture or concentrated brine at its freezing point; reducing the temperature of the aqueous mixture to a temperature equal to or below the freezing point of the aqueous mixture to form ice or hydrate and a concentrate; phase separating the concentrate and the flotation medium; recovering the concentrate; and recovering the ice or hydrate and flotation medium as a slurry. Upon melting, phase separation of the resultant water from the flotation medium may provide a purified water product.