Switchable Ionic Liquid Solvent for Acid Gas Removal
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Solution Overview
Problem
Existing methods for removing acid gases from gas mixtures, such as those containing CO2, H2S, and mercaptans, are complex and costly, particularly due to the need for expensive regeneration processes using aqueous amine solutions and distillation towers.
Innovation Solution
A process and plant utilizing switchable ionic liquids as absorption solvents, which react with acid gases to form ionic liquids that can be easily regenerated through a simple flash process, eliminating the need for complex distillation equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aqueous amine solutions are used for acid gas absorption, then effective acid gas removal is achieved, but plant complexity and operating costs increase due to required distillation towers for solvent regeneration
Solution Approach 1:
The patent changes the chemical composition parameters of the absorption solvent from traditional aqueous amine solutions to ionic liquids with specific cation-anion combinations. This parameter change enables the solvent to achieve effective acid gas absorption while allowing regeneration through simple flash evaporation at moderate temperatures, eliminating the need for complex distillation towers and significantly reducing plant complexity
Solution Approach 2:
The patent employs composite ionic liquid systems combining specific cations (such as imidazolium, pyridinium, or piperidinium) with specific anions (such as halides, carboxylates, or cyanide). These composite material structures provide both high acid gas absorption capacity and favorable regeneration characteristics, resolving the contradiction between removal effectiveness and plant complexity
2Reliability
If aqueous amine solutions are used for acid gas absorption, then effective acid gas removal is achieved, but operating costs increase due to expensive regeneration processes
Solution Approach 1:
By changing the solvent composition to ionic liquids with appropriate pKa values and thermal stability, the regeneration process can be conducted through simple flash evaporation at moderate temperatures rather than expensive distillation processes. This parameter change maintains effective acid gas removal while dramatically reducing operating costs
Solution Approach 2:
The ionic liquid solvent system is designed to be regenerable through simple flash processes, effectively allowing the solvent to be reused many times without degradation. This replaces the expensive, complex distillation regeneration process with a much more economical operation, reducing operating costs significantly
3Reliability
If dimethyl sulfoxide is used for CO2 absorption, then CO2 removal is effective, but H2S treatment becomes problematic due to precipitation of elemental sulfur that occludes the absorber column
Solution Approach 1:
The patent uses composite ionic liquid systems where the specific cation-anion combination is selected to avoid the harmful reaction between sulfoxides and H2S. The ionic liquid structure prevents elemental sulfur precipitation while maintaining effective absorption of both CO2 and H2S, resolving the contradiction between CO2 removal effectiveness and harmful sulfur precipitation
Solution Approach 2:
By changing from molecular solvents like dimethyl sulfoxide to ionic liquid systems with specific chemical parameters, the patent eliminates the harmful side reaction with H2S while preserving effective acid gas absorption. The ionic liquid's unique chemical structure prevents sulfur precipitation and maintains column operability
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 allows for effective and economical removal of acid gases, reducing operational complexity and costs compared to traditional methods, with applications in treating gas mixtures containing H2S, CO2, and mercaptans.
Implementation Method 1
the removal of acid gas(es) from the gas mixture is performed by absorption with an absorption solvent comprising particular ionic liquids
Implementation Method 2
the solvent used, after having absorbed the acid gas(es) from the gas mixture, is then regenerated
Implementation Method 3
the solvent used, after having absorbed the acid gas(es) from the gas mixture, is then regenerated in an extremely simple and effective way in a simple flash process
Data Source
AI summary
A process for treatment of gas mixtures containing acid gas, for the removal of said acid gas from the gas mixtures. The process has (A) an absorption step performed on a gas mixture containing acid gas by means of a solvent system containing at least one liquid absorption solvent for removing from the gas mixture the acid gas contained therein and forming a lean gas mixture, from which at least part of the acid gas have been removed, and an enriched solvent containing the acid gas and (B) a regeneration step, in which the enriched solvent is subjected to a gas/liquid separation step by a flash process to be separated from the absorbed acid gas and to produce an acid gas flow and a regenerated solvent, which is recirculated to the absorption step. The solvent system contains at least one liquid absorption solvent selected from switchable ionic liquids.