Ionic Liquid Absorbent for CO2 Removal
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Solution Overview
Problem
Current carbon dioxide separation technologies, particularly chemical absorbents like aqueous amine solutions and hot aqueous potassium carbonate, face issues such as high energy demands, corrosion, volatility, and instability in natural gas streams, limiting their effectiveness and safety in industrial processes.
Innovation Solution
A process using mixtures of tetrasubstituted phosphonium or tetrasubstituted ammonium ionic liquids with conjugate base anions of carboxylic acids, which are stable and effective in absorbing carbon dioxide even in the presence of water, allowing for efficient removal and desorption, thus overcoming the limitations of traditional absorbents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If aqueous amine solutions are used as chemical absorbents, then carbon dioxide absorption capacity is improved, but energy demand for regeneration increases and corrosion problems occur
Solution Approach 1:
The patent changes the chemical parameters of the absorbent by using ionic liquids with specific cation-anion combinations (e.g., imidazolium with carboxylate anions) instead of traditional aqueous amines. This parameter change allows the absorbent to maintain high CO2 absorption capacity while requiring lower regeneration temperatures, thus reducing energy demand.
Solution Approach 2:
The patent employs composite ionic liquid systems combining different cation and anion species to create absorbents that exhibit both high CO2 absorption capacity and improved thermal stability. The composite nature of these ionic liquids allows optimization of both absorption performance and regeneration energy requirements.
2Quantity of substance
If aqueous amine solutions are used as chemical absorbents, then carbon dioxide absorption capacity is improved, but corrosion of pipelines and steel parts occurs
Solution Approach 1:
The patent changes the chemical composition parameters by replacing aqueous amine solutions with ionic liquids having specific molecular structures (e.g., imidazolium cations with carboxylate anions). These ionic liquids provide high CO2 absorption capacity while exhibiting significantly reduced corrosivity toward metal surfaces, eliminating the harmful corrosion effect.
3Quantity of substance
If aqueous amine solutions are used, then carbon dioxide absorption capacity is improved, but volatility and toxicity lead to gas stream contamination and workplace hazards
Solution Approach 1:
The patent fundamentally changes the physical and chemical parameters of the absorbent by using ionic liquids, which have negligible vapour pressures compared to aqueous amines. This parameter change eliminates volatility-related contamination of the gas stream and removes toxic inhalation hazards, while ionic liquids can be engineered to maintain high CO2 absorption capacity.
4Quantity of substance
If hot aqueous potassium carbonate is used, then carbon dioxide absorption capacity is improved, but operating temperature and crystallization/precipitation issues increase
Solution Approach 1:
The patent changes the thermal parameters of the absorbent system by using ionic liquids that remain stable and liquid at lower operating temperatures. The ionic liquid structure prevents crystallization and precipitation issues that plague hot aqueous potassium carbonate systems, allowing effective CO2 absorption at moderate temperatures without phase separation or solid formation.
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 selected ionic liquid and water mixtures demonstrate enhanced carbon dioxide absorption capacity, stability, and resistance to degradation, enabling efficient and sustainable carbon dioxide removal from gaseous streams with minimal absorbent loss or contamination, and can be recycled without degradation.
Implementation Method 1
The technologies used for the purpose of carbon dioxide separation can be divided into three groups: liquid absorbents, solid absorbents or adsorbents, and membranes. Liquid absorbents are by far the most commonly used of these, and can in turn be divided into physical and chemical absorbents.
Implementation Method 2
The energy efficiency of chemical absorption processes is determined largely by the energy demands of regenerating the absorbent by desorption of the carbon dioxide.
Data Source
AI summary
The present invention relates to the separation of gases, and more specifically to an inventive process for the removal of carbon dioxide gas using carefully selected ionic liquid absorbents together with water in a carefully selected ratio.