Zeolite Catalyst XRD Ratio for Alcohol-Based NOx Reduction
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Solution Overview
Problem
Existing catalysts for removing nitrogen oxides (NOx) from combustion exhaust gases in marine diesel engines face issues such as high reducing agent costs, side reactions with alcohol, and deposition of coke or carbon compounds, leading to reduced denitration capability over time.
Innovation Solution
A denitration catalyst with zeolite as a support, having a specific relative peak intensity ratio in XRD analysis, and containing cobalt as the catalyst metal, is used with an alcohol reducing agent to enhance denitration capability, particularly in low temperature ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ammonia selective catalytic reduction method is used to remove NOx, then denitration capability is achieved, but sulfur oxide and ammonia react to form ammonium sulfate which deposits on the exhaust path causing clogging
Solution Approach 1:
The invention changes the chemical parameters by replacing ammonia with alcohol as the reducing agent, and adjusts the temperature parameter to operate above the dew point of ammonium sulfate to prevent deposition while maintaining denitration capability
Solution Approach 2:
The invention uses alcohol as a short-living reducing agent that can be completely consumed in the reaction, avoiding the accumulation and deposition problems associated with ammonia-based systems
2Reliability
If catalyst containing metal supported on zeolite with alcohol as reducing agent is used, then denitration reaction occurs, but side reactions occur causing coke deposition on catalyst surface deteriorating denitration capability over time
Solution Approach 1:
The invention optimizes the catalyst composition parameters including the type of metal, its loading amount, and the zeolite structure to enhance selectivity toward the desired denitration reaction while suppressing side reactions that lead to coke formation
Solution Approach 2:
The invention uses a composite catalyst system combining metal particles supported on zeolite with specific properties, creating a material that synergistically promotes the denitration reaction while resisting deactivation by coke deposition
3Productivity
If large amount of reducing agent is used in denitration process, then denitration reaction efficiency is improved, but carbon compounds accumulate on catalyst deteriorating denitration capability
Solution Approach 1:
The invention optimizes the reducing agent to catalyst ratio parameter and adjusts the reaction temperature parameter to achieve high denitration efficiency while minimizing carbon compound accumulation on the catalyst surface
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 solution increases the selectivity of the alcohol reducing agent in denitration reactions, improving denitration capability while maintaining efficiency with a reduced amount of reducing agent, thus enabling high-efficiency exhaust gas processing.
Implementation Method 1
a denitration catalyst containing vanadium and titania as a major component is used as a catalyst
Implementation Method 2
in a powder X-ray diffraction (XRD) measurement of the denitration catalyst a ratio (relative peak intensity ratio) r=I/J of a height I of a diffraction peak at a diffraction angle (2θ) of from 7.8 to 10.0° and a height J of a diffraction peak at a diffraction angle (2θ) of from 28.0 to 31.0° being in a range of from 3.0 to 5.0
Implementation Method 3
ammonia is used as a reducing agent
Implementation Method 4
a side reaction may occur in addition to the desired denitration reaction, a side reaction product due to the side reaction causes deposition of so-called coke (carbon) on the surface of the catalyst
Implementation Method 5
a sulfur oxide and ammonia are reacted with each other in the combustion exhaust gas to form ammonium sulfate ((NH4)2SO4)
Implementation Method 6
the denitration catalyst layer of the exhaust gas processing path where the supply of the exhaust gas is terminated is heat-treated on the spot at a temperature of from 350 to 800° C., thereby recovering the deteriorated denitration capability thereof
Data Source
AI summary
To provide a catalyst for purifying a combustion exhaust gas and a method for purifying a combustion exhaust gas. The denitration catalyst used in a method for purifying a combustion exhaust gas of removing a nitrogen oxide in the exhaust gas by making the catalyst into contact with the combustion exhaust gas having an alcohol as a reducing agent added thereto, contains zeolite as a support having supported thereon a catalyst metal, in a powder X-ray diffraction (XRD) measurement of the denitration catalyst a ratio (relative peak intensity ratio) r=I/J of a height I of a diffraction peak at a diffraction angle (2θ) of from 7.8 to 10.0° and a height J of a diffraction peak at a diffraction angle (2θ) of from 28.0 to 31.0° being in a range of from 3.0 to 5.0.