Multi-Modular Membrane Distillation for High Water Recovery

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Solution Overview

Problem

Current membrane distillation (MD) desalination processes have low water recovery compared to conventional systems, despite their potential for using low-grade heat sources, and struggle to maintain a high temperature gradient for efficient water vapor flux.

Innovation Solution

The implementation of multi-modular MD systems with series and parallel configurations, including multiple membrane modules and central heating elements, along with fillers like ceramic beads and external steam jackets, to enhance solute rejection, flux, and water recovery by maintaining a high temperature gradient and efficiently utilizing heat sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If membrane distillation is carried out at 60-90°C using low-grade heat sources, then energy efficiency and environmental sustainability are improved, but water recovery remains low compared to conventional systems

Engineering Contradiction:

Improveenergy efficiencyVSAvoidwater recovery

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The system divides the membrane distillation process into multiple stages using series-connected membrane modules. Each module operates at optimized conditions, and the cumulative effect of multiple stages achieves high water recovery (90-179% increase) while maintaining low operating temperatures (60-90°C) for energy efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A heating element is positioned before the membrane modules to preheat the feed stream to the optimal temperature range (60-90°C) before it enters the membrane system. This preliminary heating action maximizes the temperature gradient across the membrane, thereby maximizing water vapor flux and recovery while using low-grade heat sources efficiently.

Inventive Principle:

Principle #10Preliminary action

2Temperature

If membrane distillation operates at lower temperatures (60-90°C), then use of low-grade heat sources is enabled, but maintaining a high temperature gradient becomes difficult

Engineering Contradiction:

Improveoperating temperatureVSAvoidtemperature gradient

Core Design Contradiction:

TemperatureVSStability of the object's composition

Solution Approach 1:

A heating element is introduced as an intermediary component between the feed source and the membrane modules. This heating element actively maintains the temperature gradient by ensuring the feed entering the membrane system is consistently at the optimal temperature (60-90°C), compensating for the lower operating temperatures and enabling sustained high water vapor flux.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If multiple membrane modules are arranged in series with heating elements between modules, then water vapor flux and solute rejection are maximized, but system complexity increases

Engineering Contradiction:

Improvewater vapor fluxVSAvoidsystem configuration

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The system uses multiple membrane modules connected in series, with heating elements positioned between each module. This segmentation allows each module to operate independently at optimized conditions, maximizing cumulative water vapor flux and solute rejection while the modular design keeps the complexity manageable through standardized repeating units.

Inventive Principle:

Principle #1Segmentation

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 significantly enhances water vapor flux and recovery, achieving up to 90-179% increase in flux and 50.6-95.2% increase in water recovery while effectively utilizing low-grade heat sources, addressing the limitations of existing MD systems.

Implementation Method 1

maintaining a high temperature gradient throughout the module

Methodology Applied

Scientific EffectTemperature gradient: Temperature Gradient

Implementation Method 2

a first heating element positioned and operable to heat a feed stream prior to or upon introduction of the feed stream to each of the at least two MD modules

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 3

MD is a membrane-based evaporation process in which the driving force is the temperature-induced vapor pressure difference

Methodology Applied

Scientific EffectPermeation: Permeation

Implementation Method 4

The systems and methods disclosed herein maximize solute rejection and flux

Methodology Applied

Scientific EffectSolute rejection:

Implementation Method 5

a condensing media inlet operable to receive a condensing media and a condensing media outlet

Methodology Applied

Scientific EffectCondensation: Condensation

Implementation Method 6

a first heating element positioned and operable to heat a feed stream

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentUS10569223B2Systems and methods for maximizing recovery in membrane distillation

Publication Date: 2020.02.25 NANOPULSE

AI summary

Membrane distillation (MD) systems include at least two MD modules arranged in series, each of at least two MD modules including a condensing media inlet operable to receive a condensing media and a condensing media outlet, a feed inlet operable to receive a feed media and a feed outlet, and a first heating element positioned and operable to heat a feed prior to or upon introduction of the feed to a first of the at least two MD modules, wherein a stream exiting the feed outlet of the first of the at least two MD modules is introduced to the second of the at least two MD modules. Other MD systems include at least two MD modules arranged in parallel.