Vanadium-Amorphous Carbon Adsorbent for Mercury Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing adsorbents for heavy metal removal in gaseous streams, such as those from fossil fuel combustion, are ineffective in the presence of sulfur oxides and nitrogen oxides, leading to low capacity and deactivation, particularly for mercury and other toxic heavy metals.
Innovation Solution
A composition comprising vanadium and amorphous carbon, prepared by incorporating a vanadium compound onto activated carbon or charcoal in the presence of an oxidizing agent and solvent, then calcined at a temperature below 210°C, which oxidizes heavy metals to a state greater than zero, even in the presence of sulfur oxides and nitrogen oxides, with an optional second stage for adsorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional adsorbents are used for heavy metal removal, then adsorption capacity is initially adequate, but they are easily deactivated by sulfur oxides and nitrogen oxides in the gas stream
Solution Approach 1:
The invention changes the chemical state of heavy metals from elemental (Hg0) to oxidized forms (Hg2+) through controlled oxidation, transforming the removal mechanism from direct adsorption to oxidation followed by adsorption. This parameter change (oxidation state) allows the adsorbent to function effectively in the presence of SOx and NOx, resolving the deactivation issue while maintaining capacity
Solution Approach 2:
The invention introduces an oxidation step as an intermediary process between the heavy metal in the gas stream and the adsorbent. By oxidizing Hg0 to Hg2+ first, the harmful interaction between conventional adsorbents and SOx/NOx is avoided, as the oxidized mercury can be selectively adsorbed without the same deactivation mechanisms
2Loss of substance
If calcination temperature is increased to remove solvent completely, then solvent removal is more efficient, but the amorphous carbon structure may be damaged
Solution Approach 1:
The invention optimizes the calcination temperature parameter to a specific range (below 210°C) that balances two competing requirements: sufficiently high to volatilize and remove the solvent completely, yet low enough to preserve the amorphous carbon structure. This precise parameter control resolves the contradiction between solvent removal efficiency and structural stability
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 vanadium-amorphous carbon composition effectively oxidizes and removes heavy metals like mercury from gaseous streams, maintaining high removal efficiency even in the presence of sulfur oxides and nitrogen oxides, with significant reduction of heavy metal content in the product stream.
Implementation Method 1
oxidizes heavy metals to an oxidation state greater than zero
Implementation Method 2
an optional second stage for adsorption of oxidized heavy metal
Implementation Method 3
calcining the vanadium incorporated amorphous carbon in the presence of oxygen and the solvent at a calcination temperature; wherein the calcination temperature is sufficient to volatilize and remove substantially all of the solvent
Data Source
AI summary
A composition containing vanadium, and an amorphous carbon selected from the group consisting of an activated carbon, an activated charcoal, and combinations thereof, which is heated to a calcination temperature at or less than about 210° C. A method of preparing such composition is also disclosed. The composition is employed in a process to remove a heavy metal from a gaseous feed stream which can optionally include a separate heavy metal adsorption stage.