Sequentially Stacked ICP and ED Desalination System

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Solution Overview

Problem

Current desalination technologies, such as reverse osmosis and electrodialysis, face challenges in achieving energy efficiency and portability for remote, resource-limited areas due to high energy consumption, weight, and susceptibility to membrane fouling, while existing portable systems are either too large or inefficient for practical use in small-scale applications.

Innovation Solution

A sequentially stacked multi-stage desalination system combining ion concentration polarization (ICP) and electrodialysis (ED) devices, optimized for energy efficiency and membrane area efficiency, using a battery or solar power, and designed for compactness and lightweight operation, allowing for the removal of both dissolved and suspended solids from seawater.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If reverse osmosis-based portable desalination units are used, then energy efficiency is improved, but weight and power consumption increase making them unsuitable for remote applications

Engineering Contradiction:

Improvespecific energy consumptionVSAvoidsystem weight

Core Design Contradiction:

Loss of energyVSWeight of moving object

Solution Approach 1:

The system is segmented into multiple stages with different functions: first-stage ICP devices for bulk salt removal and TSS removal, second-stage ICP for further desalination, and ED device for final polishing. This segmentation allows each component to be optimized for its specific function, enabling the system to achieve RO-level energy efficiency without requiring heavy high-pressure pumping equipment.

Inventive Principle:

Principle #1Segmentation

2Loss of energy

If reverse osmosis-based portable desalination units are used, then energy efficiency is improved, but device size increases reducing portability

Engineering Contradiction:

Improvespecific energy consumptionVSAvoiddevice size

Core Design Contradiction:

Loss of energyVSVolume of moving object

Solution Approach 1:

The invention replaces the mechanical high-pressure pumping system of RO with an electromembrane system (ICP and ED) that uses electrical fields for desalination. This substitution eliminates the need for heavy pressure vessels and high-power pumps, achieving comparable energy efficiency with a much more compact and lightweight device suitable for portable applications.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If conventional electrodialysis is used, then scalability and process tunability are improved, but ability to remove suspended solids deteriorates

Engineering Contradiction:

Improveprocess tunabilityVSAvoidsuspended solids removal

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The invention merges ICP technology (which excels at TSS removal through convective transport) with ED technology (which excels at TDS removal through ion exchange membranes). The combined system maintains the process tunability and scalability of ED while adding the TSS removal capability of ICP, creating a versatile system that handles both dissolved and suspended solids effectively.

Inventive Principle:

Principle #5Merging (Combining)

4Object-affected harmful factors

If ICP process is used, then TSS removal capability is improved, but energy efficiency deteriorates for complete desalination

Engineering Contradiction:

Improvesuspended solids removalVSAvoidenergy efficiency

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The system applies partial desalination in the first-stage ICP device (removing bulk salts and all TSS), then uses second-stage ICP for further desalination, and finally employs ED for complete desalination and polishing. This staged approach allows ICP to handle the energy-intensive TSS removal and bulk desalination, while ED completes the process efficiently, achieving both TSS removal and energy efficiency.

Inventive Principle:

Principle #16Partial or excessive action

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

The system effectively produces drinkable water from brackish and seawater with reduced energy consumption and suspended solids, achieving a production rate of 0.33 L/hr with a specific energy consumption of 0.4-26.6 Wh/L, meeting World Health Organization guidelines and demonstrating unprecedented size, efficiency, and operational flexibility.

Implementation Method 1

ion concentration polarization (ICP) device... extracting ions from the aqueous saline solution in the ion concentration polarization device

Methodology Applied

Scientific EffectIon concentration polarization: Electrophoresis

Implementation Method 2

electrodialysis (ED) device... extracting additional ions from the diluate of the ion concentration polarization device in the electrodialysis device

Methodology Applied

Scientific EffectElectrodialysis: Ion Exchange

Data Source

PatentUS20250019277A1Sequentially Stacked Multi-Stage Desalination System and Method

Publication Date: 2025.01.16 MASSACHUSETTS INST OF TECH

AI summary

A sequentially stacked multi-stage desalination system includes a single pair of electrodes, including an anode and a cathode; at least one ion concentration polarization device; and at least one electrodialysis device coupled with the ion concentration polarization device and configured to receive liquid flow from the ion concentration polarization device. Each ion concentration device and electrodialysis device is positioned between the anode and the cathode.