Ionic Liquid Scrubber for Heavy Metal Oxidation
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Solution Overview
Problem
Current methods are inefficient in removing elemental heavy metals like mercury from flue gases, particularly in coal-fired power plants, due to the volatility of oxidizers like iodine and the limited oxidation potential of ionic liquids at operating temperatures.
Innovation Solution
A wet scrubber system utilizing a liquor composed of an ionic liquid and a non-volatile oxidizer, such as chlorine dioxide or iodine, which forms a stabilizing complex with halides, allowing efficient oxidation of elemental heavy metals into salts without evaporating or requiring frequent refills.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If volatile oxidizers like iodine are used to remove elemental heavy metals from flue gases, then oxidation efficiency is improved, but oxidizer loss through evaporation increases
Solution Approach 1:
The patent uses an ionic liquid as an intermediary carrier to deliver the oxidizer to the heavy metal vapor. The oxidizer is dissolved in the ionic liquid, which acts as a mediator between the oxidizer and the contaminant. This allows the oxidizer to be delivered efficiently without direct evaporation, as the ionic liquid has negligible vapor pressure.
Solution Approach 2:
The patent changes the physical state and delivery mechanism of the oxidizer by dissolving it in an ionic liquid. This parameter change transforms the oxidizer from a volatile substance that evaporates directly into a non-volatile solution that is delivered through the ionic liquid phase, thereby eliminating evaporation losses while maintaining oxidation capability.
2Loss of substance
If ionic liquids are used as scrubbing agents, then vapor pressure is reduced, but oxidation potential is insufficient at operating temperatures
Solution Approach 1:
The patent merges the advantages of ionic liquids (negligible vapor pressure) with strong oxidizers by combining them into a single scrubbing solution. The ionic liquid serves as the solvent medium while the dissolved oxidizer provides the necessary oxidation potential, creating a composite scrubbing agent that exhibits both low volatility and high oxidation capability.
Solution Approach 2:
The scrubbing solution is a composite material consisting of an ionic liquid base combined with a strong oxidizer. This composite approach allows the system to benefit from the non-volatile nature of the ionic liquid while the dissolved oxidizer component provides the required oxidation potential for effective heavy metal removal.
3Productivity
If ligands are added to bind heavy metal ions, then absorption efficiency is improved, but complexation reactions increase device complexity
Solution Approach 1:
The patent extracts or removes the ligand component from the scrubbing system, relying solely on oxidation to convert elemental heavy metals into ionic forms that can be absorbed by the ionic liquid. This elimination of the ligand step simplifies the overall process while maintaining effective heavy metal removal through the oxidation-absorption mechanism.
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 system effectively reduces heavy metal contamination in flue gases by over 99% with minimal oxidizer loss, maintaining efficiency over extended periods without environmental pollution from liquor vapors.
Implementation Method 1
The oxidizer is selected as to oxidize the elemental metal into a salt
Implementation Method 2
a liquor that contains an oxidizer dissolved in a non-volatile liquid
Data Source
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AI summary
A wet scrubber, a liquor for a wet scrubber, and a power-plant comprising a wet scrubber are described. In a preferred embodiment, the wet scrubber has a liquor containing an oxidizer in ionic liquid. Optionally, the oxidizer has, in pure state, high vapor pressure, and in the ionic liquid, the oxidizer forms a complex that has a much lower vapor pressure. In a preferred embodiment, the liquor is substantially free of any ligand that binds to the metal to be absorbed by the liquor.