Electrodialysis System Counter-Current Flow Reduces Concentration Gradient

Solution Overview

Problem

Conventional high-recovery electrodialysis systems experience high concentration gradients at high recovery rates, leading to efficiency losses such as increased osmotic pressure and thermodynamic penalty, which hinder the separation performance of the system.

Innovation Solution

The electrodialysis system is configured such that the product inlet stream of an upstream electrodialysis device is the brine outlet stream of a downstream electrodialysis device, thereby minimizing the concentration gradient across the second electrodialysis device and improving the recovery of purified water.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If conventional high-recovery electrodialysis systems operate at high recovery rates, then waste brine reduction is achieved, but concentration gradient increases leading to efficiency losses

Engineering Contradiction:

Improvewaste brineVSAvoidefficiency loss due to concentration gradient

Core Design Contradiction:

Loss of substanceVSLoss of energy

Solution Approach 1:

The patent inverts the conventional flow configuration by routing the brine outlet stream from a downstream device to become the product inlet stream for an upstream device. This reverse routing creates a counter-current flow pattern that maintains more uniform concentration gradients across all devices, reducing osmotic pressure and thermodynamic penalties while achieving high recovery rates with minimal waste brine.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces a new dimensional aspect to the flow configuration by creating a multi-dimensional stream routing where brine streams from downstream devices feed into upstream devices. This adds complexity to the flow topology, transforming the traditional linear sequence into a more sophisticated network that optimizes concentration gradient distribution across the entire system.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Loss of substance

If conventional high-recovery electrodialysis systems operate at high recovery rates, then waste brine reduction is achieved, but separation performance deteriorates due to increased osmotic pressure and thermodynamic penalty

Engineering Contradiction:

Improvewaste brineVSAvoidseparation performance

Core Design Contradiction:

Loss of substanceVSReliability

Solution Approach 1:

The patent inverts the conventional flow configuration by routing the brine outlet stream from a downstream device to become the product inlet stream for an upstream device. This reverse routing creates a counter-current flow pattern that maintains more uniform concentration gradients across all devices, reducing osmotic pressure and thermodynamic penalties while achieving high recovery rates with minimal waste brine.

Inventive Principle:

Principle #13The other way round (Inversion)

3Loss of energy

If the product inlet stream of an upstream electrodialysis device is the brine outlet stream of a downstream electrodialysis device, then concentration gradient is decreased and efficiency is improved, but system complexity increases

Engineering Contradiction:

ImproveefficiencyVSAvoidsystem configuration

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent inverts the conventional flow configuration by routing the brine outlet stream from a downstream device to become the product inlet stream for an upstream device. This reverse routing creates a counter-current flow pattern that maintains more uniform concentration gradients across all devices, reducing osmotic pressure and thermodynamic penalties while achieving high recovery rates with minimal waste brine.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent makes the brine outlet stream serve multiple functions: it is both the waste product of a downstream device and the feed material for an upstream device. This multi-functionality allows the same fluid stream to play different roles at different stages of the process, optimizing concentration gradients while reducing the need for separate waste handling systems.

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 decreases the concentration gradient, reducing osmotic pressure and thermodynamic penalty, which enhances the efficiency and recovery of the electrodialysis system, especially at high recovery rates.

Implementation Method 1

For example, an electrodialysis device can include a pair of electrodes and alternating anionic and cationic exchange membranes. A voltage can be applied to one or more of the electrodes to initiate an electrochemical reaction.

Methodology Applied

Scientific EffectElectrochemical reaction: Electrolysis

Implementation Method 2

The alternating cationic exchange membranes and anionic exchange membranes can selectively remove ions from a first stream of fluid while introducing the removed ions to an adjacent, second stream of fluid.

Methodology Applied

Scientific EffectIon exchange: Ion Exchange

Implementation Method 3

Osmotic pressure is the driving force that causes water to osmote from the dilute stream (i.e., the product stream) to the concentrate stream (i.e., brine stream).

Methodology Applied

Scientific EffectOsmotic pressure: Osmotic Pressure

Implementation Method 4

The alternating cationic exchange membranes and anionic exchange membranes can selectively remove ions from a first stream of fluid while introducing the removed ions to an adjacent, second stream of fluid.

Methodology Applied

Scientific EffectElectrostatic attraction/repulsion: Ion Repulsion/Attraction

Data Source

PatentUS12274982B2Electrodialysis systems with decreased concentration gradients at high recovery rates

Publication Date: 2025.04.15 TEXOPCO LLC

AI summary

Provided are electrodialysis systems comprising a plurality of electrodialysis devices, wherein each electrodialysis device of the plurality of electrodialysis devices has a product inlet stream, a product outlet stream, a brine inlet stream, and a brine outlet stream. The product inlet stream for a first electrodialysis device comprises the brine outlet stream of a second electrodialysis device. Further, a first portion of a feed stream is the brine inlet stream for the first electrodialysis device and a second portion of the feed stream is the brine inlet stream for the second electrodialysis device or a third electrodialysis device.