Forward Osmosis Draw Solution Ion Balance Recovery

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Solution Overview

Problem

Forward osmosis systems face challenges with ion exchange phenomena that disrupt ion balance, leading to higher salinity in product water and difficulty in recovering draw solutes, which current pre and post-treatment processes do not adequately address.

Innovation Solution

An osmotically driven membrane process that introduces a concentrated draw solution across a forward osmosis membrane to maintain osmotic concentration gradient, promotes solvent flow, and recycles ionic species to balance ion exchange, allowing for the recovery of draw solutes through a reverse osmosis system and subsequent separation processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If forward osmosis is used for desalination, then water can be separated from seawater, but ion exchange phenomena occur that disrupt ion balance and increase product water salinity

Engineering Contradiction:

Improvewater purification effectivenessVSAvoidion exchange disruption

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the harmful ionic species that cause ion exchange disruption from the system. A selective removal mechanism is implemented to take out the problematic ions (such as divalent ions) that trigger unwanted ion exchange phenomena, thereby maintaining ion balance and reducing product water salinity while preserving the water purification effectiveness of forward osmosis

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary substance or mechanism that mediates the ion exchange process. This intermediary selectively interacts with the harmful ionic species, preventing them from disrupting the ion balance in the product water, while allowing the forward osmosis process to continue effectively purifying water from seawater

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If forward osmosis is used for desalination, then water can be separated from seawater, but draw solute recovery becomes difficult

Engineering Contradiction:

Improvewater separation effectivenessVSAvoiddraw solute recovery ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent converts the harmful ion exchange phenomena into a beneficial process for draw solute recovery. By utilizing the ion exchange mechanism that was previously problematic, the system now facilitates the concentration and recovery of draw solutes in the retentate stream, making their recovery easier while maintaining effective water separation

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent implements a system where the retentate stream containing concentrated draw solutes is selectively treated and recovered. Instead of discarding this stream or treating it as waste, the system recovers the valuable draw solutes through selective removal mechanisms, converting a potential disposal problem into a resource recovery opportunity

Inventive Principle:

Principle #34Discarding and recovering

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 effectively recovers draw solutes and maintains ion balance, improving the efficiency of water purification and reducing the salinity of product water by reintroducing balanced ionic species, thereby enhancing the overall recovery process.

Implementation Method 1

a forward osmosis membrane. A second solution, or draw solution, with an increased concentration relative to that of the first or process solution may be exposed to a second opposed surface of this membrane. Solvent may then be drawn from the solution through the forward osmosis membrane

Methodology Applied

Scientific EffectOsmosis: Osmosis

Implementation Method 2

directing the recovered solvent to a reverse osmosis system, pressurizing the recovered solvent to produce a purified solvent and a concentrated solution

Methodology Applied

Scientific EffectReverse Osmosis: Reverse Osmosis

Data Source

PatentUS10280097B2Osmotic separation systems and methods

Publication Date: 2019.05.07 CHINA CAMC ENG HONGKONG CO LTD

AI summary

Separation processes using osmotically driven membrane systems are disclosed generally involving the extraction of solvent from a first solution to concentrate solute by using a second concentrated solution to draw the solvent from the first solution across a semi-permeable membrane. Enhanced efficiency may result from using low grade waste heat from industrial or commercial sources. Pre-treatment and post-treatment may also enhance the osmotically driven membrane processes.