Method for the removal of moisture from moist gas mixtures by use of ionic liquids

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Solution Overview

Problem

Existing dehumidification methods for moist gas mixtures face challenges with high electricity consumption and viscosity issues in air conditioning systems, and the tendency of ionic liquids to precipitate upon contact with CO2, leading to blockages and inefficiencies in absorption refrigeration machines.

Innovation Solution

A method using a liquid absorption medium comprising a mixture of triethylene glycol and specific salts, such as 1,3-dimethylimidazolium cation with acetate or propionate anions, which maintains low viscosity and reduces precipitation when exposed to CO2, enhancing the dehumidification process and reducing energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional air conditioning systems cool air to desired temperature, then cooling effect is achieved, but air falls below dew point causing high electricity consumption for dehumidification

Engineering Contradiction:
Improvecooling temperatureVSAvoidelectricity consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The invention separates the cooling and dehumidification functions into independent stages. First, air is cooled to a temperature above the dew point to avoid condensation. Then, the dried air is cooled further to the desired temperature. This segmentation allows cooling without unnecessary dehumidification, reducing energy consumption.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a drying medium as an intermediary substance that absorbs moisture from the air. This mediator enables dehumidification through physical absorption rather than thermal condensation, allowing the system to remove moisture without cooling air below the dew point, thus reducing energy consumption.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If ionic liquids are used as absorption medium for dehumidification, then absorption capacity is improved, but viscosity increases causing flowability problems and blockages

Engineering Contradiction:
Improveabsorption capacityVSAvoidflowability
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The invention uses composite absorption media combining ionic liquids with other substances such as deep eutectic solvents, glycols, or ionic liquid salts with specific anions. This composite approach maintains the high absorption capacity of ionic liquids while reducing viscosity by incorporating lower-viscosity components, thereby improving flowability and preventing blockages.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical parameters of the absorption medium by selecting specific ionic liquid compositions, such as imidazolium-based ionic liquids with particular anions (e.g., acetate, propionate, butyrate). These parameter changes optimize the balance between absorption capacity and viscosity, ensuring both effective dehumidification and adequate flowability for system operation.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If ionic liquids contact CO2 in gas mixtures, then dehumidification process continues, but precipitation occurs leading to blockages in cavities

Engineering Contradiction:
Improvedehumidification efficiencyVSAvoidsystem reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention employs absorption media with specific ionic liquid compositions that are less prone to precipitation with CO2. While the absorption medium may require periodic replacement or regeneration, its resistance to precipitation ensures continuous reliable operation without blockages, maintaining both productivity and system reliability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the chemical composition parameters of the ionic liquid to reduce CO2 solubility and precipitation tendency. By selecting specific cation-anion combinations and controlling purity levels, the system maintains dehumidification efficiency while preventing the formation of solid precipitates that would cause blockages and reliability issues.

Inventive Principle:
Principle #35Parameter changes

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 solution effectively dehumidifies moist gas mixtures with lower water content and higher flowability, reducing energy consumption and preventing blockages, thereby improving the economic efficiency and reliability of dehumidification systems.

Implementation Method 1

method for dehumidifying a moist gas mixture with a liquid absorption medium, which is a mixture of triethylene glycol and at least one salt

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

the water-laden drying medium is regenerated by heating it to a temperature at which the water is desorbed again

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

The moist gas mixture is created when water evaporates under low pressure

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3257568B1Method for the removal of moisture from moist gas mixtures by use of ionic liquids
Publication Date: 2019.09.18 EVONIK OPERATIONS GMBH
  • EP3257568B1 patent drawingFigure 1
  • EP3257568B1 patent drawingFigure 2

AI summary

The invention relates to a method for dehumidifying a moist gas mixture and the absorption medium used in the method. The invention also relates to a device for dehumidifying a moist gas mixture and its use in the method according to the invention.