SCR Catalyst Protection Using Kaolin and Iron Halides
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Solution Overview
Problem
SCR catalysts in boilers and kilns are prone to deactivation due to poisoning by gaseous potassium, sodium, and phosphorus compounds, leading to reduced NOx reduction efficiency and shorter catalyst life, with existing solutions failing to effectively resist poisoning by these compounds.
Innovation Solution
Introducing kaolin-bearing compounds into the combustion zone to react with gaseous potassium and sodium compounds, forming less reactive aluminosilicate compounds, and using iron-bearing halide compounds to react with phosphorus and mercury compounds, thereby sequestering these contaminants before they reach the SCR catalyst.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SCR catalyst is used to reduce NOx emissions, then NOx reduction efficiency is improved, but catalyst deactivation occurs due to poisoning by gaseous potassium, sodium, and phosphorus compounds
Solution Approach 1:
The patent introduces kaolin-bearing compounds and iron-bearing halide compounds into the combustion zone before the flue gas reaches the SCR catalyst. These compounds react with gaseous potassium, sodium, and phosphorus compounds in advance to form less reactive species, preventing them from poisoning the catalyst. This preliminary action preserves catalyst activity and extends its operational life while maintaining NOx reduction efficiency.
Solution Approach 2:
The patent uses kaolin-bearing compounds and iron-bearing halide compounds as intermediary substances that mediate between the harmful gaseous compounds and the SCR catalyst. These intermediaries react with the poisonous gaseous species to form less reactive compounds, thereby protecting the catalyst from direct exposure to poisons while allowing the SCR system to continue functioning effectively.
2Reliability
If kaolin-bearing compounds are introduced to react with gaseous potassium and sodium compounds, then catalyst poisoning is reduced, but additional substances are added to the combustion process
Solution Approach 1:
The patent changes the chemical form of gaseous potassium, sodium, and phosphorus compounds by introducing kaolin-bearing and iron-bearing halide compounds. These reactions transform the harmful gaseous species into less reactive compounds with different chemical parameters, reducing their poisoning potential while managing the quantity of substances in the combustion zone.
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 method significantly extends the active life of the SCR catalyst by reducing the formation of gas-phase potassium, sodium, and phosphorus species, minimizing catalyst deactivation and maintaining NOx reduction efficiency, while also controlling mercury emissions.
Implementation Method 1
Introducing kaolin-bearing compounds into the combustion zone to react with gaseous potassium and sodium compounds, forming less reactive aluminosilicate compounds
Implementation Method 2
using iron-bearing halide compounds to react with phosphorus and mercury compounds, thereby sequestering these contaminants before they reach the SCR catalyst
Data Source
AI summary
The present invention relates generally to the field of emission control equipment for boilers, heaters, kilns, or other flue gas-, or combustion gas-, generating devices (e.g., those located at power plants, processing plants, etc.) and, in particular to a new and useful method and apparatus for preventing the poisoning and/or contamination of an SCR catalyst. In another embodiment, the method and apparatus of the present invention is designed to protect an SCR catalyst, while simultaneously providing emission control.