Hygroscopic Fluid Gas Conditioning Moisture Equilibrium

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Solution Overview

Problem

Liquid-gas contactors used in gas processing consume large amounts of water and produce significant waste water due to moisture evaporation and contamination, limiting their efficiency and requiring extensive treatment and disposal.

Innovation Solution

The use of a hygroscopic working fluid, such as a solution of calcium chloride or lithium chloride, to achieve moisture equilibrium with the process gas, reducing evaporation and waste water production by acting as a medium for aqueous-phase absorption or reaction, and allowing for recirculation and separation of reaction products.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If water is used as the liquid medium in liquid-gas contactors, then effective gas conditioning is achieved, but water consumption increases and waste water production increases

Engineering Contradiction:
Improvegas conditioning effectivenessVSAvoidwater consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent changes the chemical composition parameters of the liquid medium from pure water to a salt solution (containing NaCl, CaCl2, MgCl2, or their mixtures). This parameter change allows the liquid to achieve moisture equilibrium with the flue gas without continuous evaporation, thereby reducing water consumption while maintaining gas conditioning effectiveness. The salt solution creates an equilibrium moisture content that prevents excessive water evaporation into the gas stream.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a copy of the natural moisture equilibrium mechanism found in hygroscopic materials. By using salt solutions that naturally absorb and release moisture to maintain equilibrium, the system replicates the behavior of hygroscopic substances without requiring large volumes of water, thus reducing water consumption while preserving the gas conditioning function.

Inventive Principle:
Principle #26Copying

2Reliability

If water is used as the liquid medium in liquid-gas contactors, then effective gas conditioning is achieved, but waste water production increases requiring treatment and disposal

Engineering Contradiction:
Improvegas conditioning effectivenessVSAvoidwaste water production
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition from pure water to a salt solution, which fundamentally alters the evaporation and condensation behavior. The salt solution maintains moisture equilibrium with the flue gas, preventing excessive water evaporation and subsequent waste water generation. This parameter change eliminates the need for large volumes of water circulation and reduces waste water production to minimal levels requiring only basic treatment.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the typically harmful effect of evaporation (which causes water loss and waste water generation) into a beneficial equilibrium process. The salt solution's hygroscopic properties cause it to automatically absorb and release moisture to maintain equilibrium with the flue gas, turning evaporation from a harmful loss mechanism into a self-regulating equilibrium process that minimizes water consumption and waste water production.

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

3Reliability

If moisture is allowed to evaporate into the process gas stream, then gas conditioning occurs, but water is continually lost

Engineering Contradiction:
Improvegas conditioning effectivenessVSAvoidwater loss via evaporation
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent changes the vapor pressure parameters of the liquid medium by dissolving salts in water. The salt solution has lower vapor pressure than pure water, which reduces the driving force for evaporation. Combined with the hygroscopic properties of the salt solution, this creates a dynamic equilibrium where moisture transfer between liquid and gas is minimized, thereby reducing water loss while maintaining gas conditioning effectiveness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful continuous evaporation process into a beneficial equilibrium moisture exchange. The salt solution's ability to absorb and release moisture creates a self-regulating system that maintains optimal humidity in the flue gas without continuous water loss. The evaporation that does occur is balanced by condensation, turning a one-way loss mechanism into a reversible equilibrium process.

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

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 reduces water consumption and waste water production while maintaining effective gas conditioning, allowing for independent control of operating temperatures and facilitating heat recovery, thereby optimizing the gas-conditioning process.

Implementation Method 1

contacting a process gas with a hygroscopic working fluid in order to remove a constituent from the process gas

Methodology Applied
Scientific EffectHygroscopic absorption: Absorption (physical)

Implementation Method 2

achieve moisture equilibrium with the process gas, reducing evaporation and waste water production

Methodology Applied
Scientific EffectMoisture equilibrium: Absorption (physical)

Implementation Method 3

the hygroscopic working fluid may act as a liquid medium to support aqueous-phase absorption of the constituent from the process gas

Methodology Applied
Scientific EffectAqueous-phase absorption: Absorption (physical)

Implementation Method 4

or to support chemical reaction of the constituent within a liquid-gas contactor

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 5

allowing for independent control of operating temperatures and facilitating heat recovery

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3415223B1Water-saving liquid-gas contact processes based on equilibrium moisture operation
Publication Date: 2023.09.13 ENERGY & ENVIRONMENTAL RESEARCH CENTER FOUNDATION
  • EP3415223B1 patent drawingFigure 1~2
  • EP3415223B1 patent drawingFigure 3~4
  • EP3415223B1 patent drawingFigure 5~6

AI summary

A method for treating a process gas, comprising contacting a cooled process gas inlet stream in a liquid-gas contactor (16) at an operating temperature managed by the temperature of the process gas inlet stream with a hygroscopic working fluid at an equilibrium concentration for the desiccant with a process gas inlet stream, the hygroscopic fluid comprising a desiccant and a component adapted to absorb or react with a pollutant or contaminant in the process gas, wherein the operating temperature of the liquid-gas contactor and moisture content of the process gas inlet stream are within the moisture equilibrium boundary for the hygroscopic working fluid, the moisture equilibrium boundary being based on the desiccant as a function of the moisture content of the process gas inlet stream and the operating temperature of the liquid-gas contactor above which the hygroscopic working fluid loses moisture.