Segmented Sorbent for Mercury Removal in High Sulfur Flue Gas
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for mercury removal from flue gas streams containing high concentrations of sulfur oxides, such as sulfur trioxide, are inefficient due to interference from sulfur compounds, which reduce the effectiveness of activated carbon injection systems and require large amounts of alkaline or reactive agents, increasing costs and complexity.
Innovation Solution
A dry sorbent composition comprising a porous mercury adsorptive material with a mean particle diameter of less than 12 µm, combined with an acid gas suppression agent like ammonium bromide, enhances mercury removal by suppressing sulfur oxide adsorption and maintaining pore volume for mercury adsorption, allowing for effective mercury removal without independent injection of alkaline agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If activated carbon injection is used for mercury removal, then mercury adsorption capacity is high, but sulfur oxides interfere with mercury removal by preferential adsorption
Solution Approach 1:
The sorbent is segmented into multiple functional components: activated carbon particles (for mercury adsorption) and alkaline agent particles (for sulfur oxide neutralization). This segmentation allows each component to target specific interferents, with activated carbon handling mercury and alkaline agents handling sulfur oxides, thereby resolving the interference problem while maintaining high mercury removal efficiency
Solution Approach 2:
Alkaline agents act as intermediary substances that neutralize sulfur oxides before they can interfere with mercury adsorption on activated carbon. The alkaline agents convert sulfur trioxide and sulfur dioxide into sulfates and sulfites, effectively mediating the harmful interaction between sulfur oxides and the activated carbon-sulfur mechanism, thus protecting mercury removal efficiency
2Object-affected harmful factors
If large amounts of alkaline agents are injected to control sulfur oxides, then sulfur oxide removal is improved, but system complexity and cost increase
Solution Approach 1:
The invention merges the mercury removal function and sulfur oxide control function into a single integrated sorbent injection system. By combining activated carbon particles with alkaline agent particles in a unified injection mechanism, the system eliminates the need for separate injection systems for each function, thereby reducing device complexity and operational burden while maintaining effective control of both mercury and sulfur oxides
3Reliability
If activated carbon is used in high sulfur environments, then mercury adsorption occurs, but pore volume is reduced due to sulfur compound adsorption
Solution Approach 1:
The invention extracts the sulfur oxide neutralization function from the activated carbon structure by introducing separate alkaline agent particles. This extraction prevents sulfur oxides from occupying pores within the activated carbon, as the alkaline agents intercept and neutralize sulfur oxides in the gas stream before they can adsorb onto the activated carbon surface, thereby preserving the full pore volume available for mercury adsorption
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 sorbent composition achieves higher mercury removal efficiency in flue gas streams with high sulfur oxide concentrations, reducing the amount of alkaline agents needed and minimizing impacts on balance-of-plant operations, while maintaining effective mercury capture and stability.
Implementation Method 1
Activated carbon is a highly porous, non-toxic, readily available material that has a high affinity for mercury vapor. Mercury is adsorbed while the carbon is conveyed in the flue gas stream
Implementation Method 2
a number of prior art solutions have been proposed wherein gross reductions in total sulfur oxide levels are achieved in the gas phase. Nearly all of these solutions rely upon bulk injections of alkaline or other reactive agents into the flue gas to react chemically with the sulfur oxides, forming salt particulates in the gas phase
Implementation Method 3
Water vapor in the flue gas further compounds the problem by combining with sulfur trioxide to form sulfuric acid in the pores of the carbon
Data Source
AI summary
Methods and systems for reducing mercury emissions from fluid streams having a high concentration of sulfur oxide species are provided herein.