Puzzolane Adsorbent for Mercury Removal in Combustion Gas Purification
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Solution Overview
Problem
Current methods for purifying combustion gases from power plants, particularly those using activated carbon, face limitations such as flammability issues, incomplete desorption at high temperatures, and contamination of fly-ashes, which complicates their reuse in concrete production.
Innovation Solution
The use of Puzzolanes with at least 5% by weight of silicon or aluminium compounds that dissolve under acidic, elevated temperature, or humid conditions, increasing their surface area and enhancing their adsorptive capacity for toxic substances like mercury without pre-treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If activated carbon is used for adsorption, then adsorptive capacity is improved, but flammability risk increases
Solution Approach 1:
The patent changes the chemical composition parameters of the adsorbent material from carbon-based (activated carbon) to silicate-based (Puzzolane) materials. This parameter change maintains high adsorptive capacity while eliminating flammability, as silicates are inherently non-flammable. The specific parameter change involves using materials with specific surface areas and pore structures that match or exceed activated carbon's performance.
Solution Approach 2:
The patent employs inexpensive silicate materials (Puzzolanes) that can be used directly without the need for expensive activated carbon. These materials are naturally occurring or easily produced industrial by-products that provide comparable adsorption performance at lower cost and without safety hazards.
2Quantity of substance
If activated carbon is used for adsorption, then adsorptive capacity is improved, but fly-ash quality deteriorates
Solution Approach 1:
The patent extracts the harmful activated carbon from the system and replaces it with Puzzolane materials. This extraction eliminates the contamination problem where activated carbon adsorbs concrete aggregates and air void formers, thereby preserving fly-ash quality for concrete production while maintaining adsorption effectiveness.
Solution Approach 2:
The patent creates a substitute adsorbent (Puzzolane-based material) that copies the essential function of activated carbon (adsorption of toxic substances) without replicating its harmful side effects (contamination of fly-ash). The silicate-based material provides similar surface area and pore structure properties needed for adsorption.
3Duration of action of stationary object
If thermal desorption is used for regeneration, then absorbent reusability is improved, but desorption completeness worsens
Solution Approach 1:
The patent changes the regeneration approach from thermal desorption to chemical or physical regeneration methods using silicate materials. The parameter change involves using lower temperatures and alternative regeneration mechanisms that achieve complete desorption without the limitations of thermal methods, thereby improving both reusability and desorption completeness.
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
Puzzolanes demonstrate a significantly higher purification capability for combustion gases, effectively removing toxic substances like mercury without the drawbacks of activated carbon, including no flammability and no impairment of fly-ashes quality for concrete production.
Implementation Method 1
A major criterion for selecting a material suitable as an adsorbent is its active surface area... The use of Puzzolanes, which comprise a portion of matter of at least about 5 % by weight, that are dissolved away under the conditions prevailing during a purification process
Implementation Method 2
Puzzolanes, which comprise a portion of matter of at least about 5 % by weight, that are dissolved away under the conditions prevailing during a purification process
Data Source
AI summary
A process for removing substances from fluids, especially from exhaust gases of combustion plants, is described. In the process Puzzolanes are used from which under the conditions prevailing during the purification process at least 5% by weight of silicon-/aluminium-compounds are dissolved away in situ.