Ionic Liquid Absorbent for CO2 Separation

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Solution Overview

Problem

Current carbon dioxide separation technologies, particularly using liquid chemical absorbents, face challenges such as high energy demands, corrosion issues, volatility of amines, and instability of imidazolium ionic liquids when exposed to natural gas streams, limiting their effectiveness and safety in industrial processes.

Innovation Solution

A process utilizing a mixture of ionic liquids with anions as conjugate bases of acids having a pKa of at least 3.60 and water, which enhances carbon dioxide absorption capacity, stability, and resistance to degradation, allowing for efficient and safe removal of carbon dioxide and water vapor from gas streams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If liquid chemical absorbents (such as aqueous amine solutions) are used for carbon dioxide removal, then carbon dioxide absorption capacity is improved, but energy demand increases due to high temperature regeneration requirements

Engineering Contradiction:

Improvecarbon dioxide absorption capacityVSAvoidenergy demand

Core Design Contradiction:

Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent changes the chemical parameters of the absorbent by using ionic liquids with specific anions (conjugate bases of acids having pKa of at least 3.60) that enable carbon dioxide absorption at lower temperatures, thereby reducing energy demand while maintaining absorption capacity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite ionic liquid systems combining specific cations (tetrasubstituted phosphonium, tetrasubstituted ammonium, trisubstituted sulfonium, guanidinium, or quinolinium) with specific anions to create an absorbent material that achieves both high CO2 absorption capacity and low energy demand

Inventive Principle:

Principle #40Composite materials

2Productivity

If conventional liquid chemical absorbents are used, then carbon dioxide removal efficiency is improved, but corrosion issues arise in pipelines and equipment

Engineering Contradiction:

Improvecarbon dioxide removal efficiencyVSAvoidcorrosion

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical properties of the absorbent by selecting ionic liquids with specific anion types (conjugate bases of acids having pKa of at least 3.60) that reduce corrosion while maintaining CO2 removal efficiency

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The ionic liquid absorbents can be easily replaced or regenerated without causing corrosion damage to infrastructure, allowing for a more sustainable and less damaging approach compared to conventional absorbents

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Quantity of substance

If imidazolium ionic liquids are used for carbon dioxide absorption, then absorption capacity is improved, but stability deteriorates when exposed to natural gas streams

Engineering Contradiction:

Improvecarbon dioxide absorption capacityVSAvoidstability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical composition parameters by specifying precise cation and anion combinations in the ionic liquid structure, where the anion is a conjugate base of an acid with pKa of at least 3.60, thereby improving stability while maintaining absorption capacity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates stable composite ionic liquid systems by combining specific cations (tetrasubstituted phosphonium, tetrasubstituted ammonium, trisubstituted sulfonium, guanidinium, or quinolinium) with specific anions that resist degradation in natural gas streams

Inventive Principle:

Principle #40Composite materials

4Productivity

If volatile amine absorbents are used, then carbon dioxide absorption efficiency is improved, but safety deteriorates due to volatility and toxicity

Engineering Contradiction:

Improvecarbon dioxide absorption efficiencyVSAvoidsafety

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes the physical and chemical parameters of the absorbent by using ionic liquids with negligible vapor pressure, thereby eliminating volatility and toxicity issues while maintaining high CO2 absorption efficiency

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The ionic liquid absorbents provide a safer alternative that can be easily contained and managed without the safety hazards associated with volatile amines, allowing for more secure industrial implementation

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 ionic liquid-water mixtures demonstrate improved carbon dioxide absorption capacity, stability, and resistance to contaminants, enabling efficient and safe separation of carbon dioxide and water vapor, with the ability to be recycled without loss or degradation, thus addressing the limitations of existing technologies.

Implementation Method 1

contacting the gaseous stream with a carbon dioxide absorbent comprising a mixture of an ionic liquid and water

Methodology Applied

Scientific EffectChemical absorption: Absorption (physical)

Implementation Method 2

separation of carbon dioxide and water vapor from gas streams

Methodology Applied

Scientific EffectPhysical absorption: Absorption (physical)

Data Source

PatentUS8734744B2Separation of gases

Publication Date: 2014.05.27 PETROLIAM NASIONAL BHD

AI summary

Aspects of the disclosure relate to the separation of gases and to a process for the removal of carbon dioxide gas using liquid absorbents. A process is disclosed for removing carbon dioxide from a gaseous stream comprising contacting the gaseous stream with a carbon dioxide absorbent comprising a mixture of an ionic liquid and water in a molar ratio of from 10:1 to 1:10, wherein the ionic liquid has the formula: [Cat+][X−].