Forward Osmosis Desalination with Cloud Point Solutes

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Solution Overview

Problem

Current desalination technologies, such as reverse osmosis, require high pressures and extensive pre-treatment, leading to high capital and operating costs, and there is a need for more energy-efficient and cost-effective methods for purifying seawater and brackish water.

Innovation Solution

The use of forward osmosis with cloud-point solutes to create high osmotic pressure differentials, allowing for the purification of water with lower energy requirements and costs, and the recycling of permeate through cloud-point extraction, utilizing a semi-permeable membrane and a precipitation system to separate and reuse cloud-point solutes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If reverse osmosis is used for desalination, then water purification is achieved, but high pressure requirements and high costs increase

Engineering Contradiction:

Improvewater purification effectivenessVSAvoidoperating pressure

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The patent inverts the traditional reverse osmosis approach by using forward osmosis, where water naturally flows from the saline side to the draw solution side driven by osmotic pressure differential, eliminating the need for high external pressure application while achieving the same purification goal

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the operating parameters by using a draw solution with cloud point solutes that create high osmotic pressure differentials, allowing the process to operate at low or zero applied pressure while maintaining effective water flux through the membrane

Inventive Principle:

Principle #35Parameter changes

2Reliability

If reverse osmosis is used for desalination, then water purification is achieved, but capital and operating costs increase

Engineering Contradiction:

Improvewater purification effectivenessVSAvoidsystem cost

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent recovers and reuses the draw solution after water extraction by heating it to precipitate the cloud point solutes, filtering them out, and recycling them back into the system, which reduces operating costs and minimizes waste disposal requirements

Inventive Principle:

Principle #34Discarding and recovering

Solution Approach 2:

The patent utilizes the phase transition of cloud point solutes from dissolved state to precipitated state through temperature change, enabling easy separation and recovery of the draw solution components without requiring energy-intensive distillation or other complex separation processes

Inventive Principle:

Principle #36Phase transitions

3Reliability

If reverse osmosis is used for desalination, then water purification is achieved, but energy consumption increases

Engineering Contradiction:

Improvewater purification effectivenessVSAvoidenergy requirement

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent inverts the energy-intensive compression approach of reverse osmosis by utilizing natural osmotic pressure gradients, where water flows spontaneously from low osmotic pressure (saline water) to high osmotic pressure (draw solution) regions without requiring external energy input for pressurization

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent uses thermal energy efficiently by applying minimal heat to precipitate cloud point solutes from the draw solution, which is a low-energy phase transition process compared to the high-energy requirements of reverse osmosis pump operation and membrane cleaning

Inventive Principle:

Principle #36Phase transitions

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 approach enables the operation of fluid purification systems with lower energy requirements, higher efficiency, and lower costs compared to traditional methods, achieving higher flux rates and reducing the cost of desalinated water to be comparable to natural freshwater sources.

Implementation Method 1

forward osmosis of water from the salt water can be driven by utilizing the osmotic pressure differential

Methodology Applied

Scientific EffectForward osmosis: Osmosis

Implementation Method 2

cloud point solutes to generate high osmotic pressure differentials with the salt water or fluid to be treated

Methodology Applied

Scientific EffectOsmotic pressure: Osmotic Pressure

Implementation Method 3

cloud point solutes to generate high osmotic pressure differentials... cloud-point extraction... cloud point precipitation

Methodology Applied

Scientific EffectCloud point precipitation: Phase Change

Data Source

PatentUS8021553B2Systems and methods for forward osmosis fluid purification using cloud point extraction

Publication Date: 2011.09.20 JFE ENGINEERING CORP

AI summary

A process for purification of fluids, for example, desalination of seawater or brackish water, using organic solutes in a concentrated water solution for use in a forward osmosis process, to extract fresh water out of salt water through the forward osmosis membrane, and subsequently separating the organic solutes out of the diluted forward osmosis permeate by cloud point extraction, thereby regenerating a concentrated organic solution for recycling to the forward osmosis process, and fresh water for potable water use.