Gradient Catalyst Bodies for NOx Reduction
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Solution Overview
Problem
Current catalyst systems for nitrogen oxide reduction in flue gases inadvertently increase sulfur dioxide oxidation, leading to undesirable formation of sulfur trioxide and corrosion issues, opacity in stack gases, and increased power costs.
Innovation Solution
The development of structural catalyst bodies with heterogeneous distributions of catalytic materials, featuring gradients of catalytic materials along their surfaces, which reduce sulfur dioxide oxidation during nitrogen oxide removal, ensuring uniform catalytic activity and minimizing sulfur trioxide formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional catalyst systems are used for nitrogen oxide reduction, then nitrogen oxide removal efficiency is improved, but sulfur dioxide oxidation increases leading to sulfur trioxide formation
Solution Approach 1:
The patent applies local quality by creating a gradient distribution of catalytic materials within the catalyst body. The catalytic material concentration varies spatially, with higher concentrations in regions optimized for nitrogen oxide reduction and lower concentrations in regions that would otherwise promote sulfur dioxide oxidation. This non-uniform distribution allows different zones of the catalyst to perform different functions, resolving the contradiction between nitrogen oxide removal efficiency and sulfur trioxide formation.
Solution Approach 2:
The patent changes the concentration parameter of the catalytic material throughout the catalyst body structure. By varying the catalytic material concentration from high to low across different regions (creating a gradient), the catalyst optimizes its performance characteristics. This parameter change enables the catalyst to maintain high nitrogen oxide reduction activity while simultaneously reducing unwanted sulfur dioxide oxidation activity.
2Ease of manufacture
If catalyst material is uniformly distributed, then manufacturing simplicity is maintained, but catalytic activity uniformity across the catalyst body is reduced
Solution Approach 1:
The patent implements local quality through a gradient distribution of catalytic materials, where the concentration and/or composition of active catalytic components varies systematically across different regions of the catalyst body. This creates zones with different catalytic properties optimized for different functions: regions with higher catalytic material concentration handle nitrogen oxide reduction, while regions with lower concentration minimize sulfur dioxide oxidation. This spatial variation in local quality resolves the contradiction between manufacturing simplicity and catalytic activity uniformity.
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 use of gradient-distributed catalytic materials in catalyst bodies effectively reduces sulfur dioxide oxidation during nitrogen oxide reduction, maintaining uniform catalytic activity and minimizing sulfur trioxide formation, thus addressing environmental and operational concerns.
Implementation Method 1
catalyst bodies described herein are operable for the selective catalytic reduction of nitrogen oxides in a flue gas stream
Implementation Method 2
The denitration reaction comprises the reaction of nitrogen oxide species in the gases, such as nitrogen oxide (NO) or nitrogen dioxide (NO2), with a nitrogen containing reductant, such as ammonia or urea, resulting in the production of diatomic nitrogen (N2) and water
Implementation Method 3
Catalyst systems for the removal of nitrogen oxides can increase the amount of sulfur dioxide oxidation since catalytic material utilized in selective catalytic reduction can additionally effectuate the oxidation of sulfur dioxide
Data Source
AI summary
In one aspect, structural catalyst bodies comprising one or more gradients of catalytic material are provided herein. In some embodiments, a structural catalyst body described herein comprises an inner partition wall having a first surface and a second surface opposite the first surface, the inner partition wall having a gradient of catalytic material along the width of the inner partition wall.