Silver Catalyst NOx Reduction Ammonia Consumption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for reducing nitrogen oxides in exhaust gases from stationary combustion sources, such as coal-fired power plants, are inefficient due to high ammonia consumption and the production of undesirable by-products.
Innovation Solution
A method using a silver-based catalytic material supported on hydroxylated alumina, in conjunction with hydrogen or hydrocarbon reductants, to selectively reduce nitrogen oxides and produce ammonia, which can then be used to further reduce nitrogen oxides, potentially eliminating the need for exogenous ammonia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional SCR or SNCR systems are used to reduce nitrogen oxides, then nitrogen oxide levels are reduced, but ammonia consumption is high and undesirable by-products are produced
Solution Approach 1:
The patent changes the chemical parameters of the reduction process by using a silver-based catalyst that enables hydrocarbon reductants to convert nitrogen oxides to ammonia with high selectivity, rather than directly converting to nitrogen as in conventional SCR. This parameter change in reaction pathway and catalyst type reduces ammonia consumption while maintaining NOx reduction efficiency
Solution Approach 2:
The patent converts the harmful nitrogen oxides into beneficial ammonia through a selective reduction process, rather than simply converting them to nitrogen. The produced ammonia can then be used to further reduce remaining nitrogen oxides, creating a cascading benefit that reduces overall ammonia consumption from external sources
2Object-affected harmful factors
If conventional SCR or SNCR systems are used to reduce nitrogen oxides, then nitrogen oxide levels are reduced, but undesirable by-products are produced
Solution Approach 1:
The patent changes the reaction parameters by using a silver-based catalyst with specific properties that promote selective formation of ammonia from nitrogen oxides and hydrocarbons. This catalytic parameter change increases selectivity for the desired ammonia product while minimizing side reactions that produce undesirable by-products
Solution Approach 2:
The silver-based catalyst acts as an intermediary that facilitates a controlled reaction pathway between nitrogen oxides and hydrocarbon reductants. This intermediary catalyst enables selective conversion to ammonia while preventing the formation of undesirable by-products through its specific catalytic properties
3Loss of substance
If ammonia is produced in-situ from nitrogen oxides and hydrocarbon reductants, then exogenous ammonia may be eliminated, but the process requires high conversion and selectivity
Solution Approach 1:
The patent achieves high conversion and selectivity by changing the catalyst parameters to silver-based materials with specific properties, and by optimizing reaction conditions such as temperature and hydrocarbon-to-NOx ratio. These parameter changes enable in-situ ammonia production with sufficient efficiency to eliminate or minimize exogenous ammonia requirements
Solution Approach 2:
The system produces its own ammonia reductant in-situ from the hydrocarbon fuel and nitrogen oxides, making the system self-sufficient. The ammonia generated from the selective reduction process is then used to reduce remaining nitrogen oxides, creating a self-service cycle that eliminates or minimizes the need for external ammonia supply
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
This approach achieves high conversion and selectivity for ammonia production, reducing nitrogen oxide levels effectively while minimizing the production of undesirable by-products, thus offering a more efficient and cost-effective solution for nitrogen oxide reduction.
Implementation Method 1
A method for treating exhaust from stationary combustion source, such as a coal-fired power plant, comprising nitrogen oxide (NOx) using a selective reduction catalyst, such as a silver-based catalytic material
Implementation Method 2
a reductant comprising hydrogen, such as hydrogen gas or a hydrocarbon
Implementation Method 3
to selectively reduce nitrogen oxides and produce ammonia
Data Source
AI summary
Provided is a process for treating nitrogen oxide-containing exhaust produced by a stationary combustion source by the catalytic reduction of nitrogen oxide in the presence of a reductant comprising hydrogen, followed by ammonia selective catalytic reduction to further reduce the nitrogen oxide level in the exhaust.