Low-Temperature SCR Catalyst Composition for Exhaust Denitration
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Solution Overview
Problem
Conventional nitrogen oxide removal catalysts using vanadium oxide on a titanium oxide carrier require high temperatures and have limited efficiency at low temperatures, necessitating a catalyst with improved denitration efficiency at lower temperatures.
Innovation Solution
A denitration catalyst comprising vanadium oxide as the main component with at least 50 wt% and a second metal, such as tungsten, cobalt, or copper, to enhance denitration efficiency at temperatures as low as 200°C or lower.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional vanadium oxide catalyst on titanium oxide carrier is used, then catalyst stability is improved, but denitration efficiency at low temperature deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the catalyst by incorporating specific metals (Cu, Zn, Mo, W, Ni, Co, Mn, Fe) in controlled amounts (0.1-20 wt% each) alongside vanadium oxide (40-70 wt%). This compositional parameter adjustment enables the catalyst to achieve high denitration efficiency at low temperatures (200-400°C) while maintaining stability, resolving the contradiction between low-temperature activity and catalyst stability.
Solution Approach 2:
The invention creates a composite catalyst material combining vanadium oxide with multiple metal oxides (CuO, ZnO, MoO3, WO3, NiO, CoO, MnO2, Fe2O3) and titanium oxide carrier. This composite structure synergistically combines the low-temperature activity of vanadium-based compounds with the stability of titanium oxide, while additional metals enhance specific functions such as sulfur oxide resistance and low-temperature performance.
2Productivity
If vanadium oxide content is increased to improve denitration activity, then nitrogen oxide reduction rate is improved, but sulfur oxide oxidation increases
Solution Approach 1:
The invention optimizes the vanadium oxide content parameter to a specific range (40-70 wt%) rather than using high concentrations, and balances it with other metal oxides (0.1-20 wt% each). This parameter optimization achieves high nitrogen oxide reduction rates while the presence of other metals suppresses excessive sulfur oxide oxidation, preventing catalyst deactivation.
Solution Approach 2:
The invention converts the potential harm of sulfur oxide oxidation into a benefit by using specific metal combinations (particularly Cu, Zn, Mo, W) that have selective catalytic properties. These metals promote nitrogen oxide reduction while being less active toward sulfur oxide oxidation, effectively converting the challenge of sulfur presence into an opportunity for selective catalysis.
3Productivity
If high temperature operation is used to improve denitration efficiency, then nitrogen oxide removal rate is improved, but energy consumption increases
Solution Approach 1:
The invention changes the operational temperature parameter from conventional high temperatures (350-400°C) to lower temperatures (200-400°C) by modifying the catalyst composition. The optimized mix of vanadium oxide (40-70 wt%) with other metal oxides (0.1-20 wt% each) lowers the activation energy required for nitrogen oxide reduction, enabling efficient denitration at reduced temperatures and thus decreasing energy consumption.
4Productivity
If catalyst is designed for high temperature operation, then denitration activity is improved, but device design flexibility is limited
Solution Approach 1:
The invention changes the temperature parameter range for catalyst operation from narrow high-temperature range (350-400°C) to broader lower temperature range (200-400°C). The composite catalyst formulation with vanadium oxide (40-70 wt%) and multiple metal oxides (0.1-20 wt% each) provides robust activity across this expanded range, enabling greater device design flexibility for various application scenarios including space-constrained and low-temperature environments.
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 catalyst achieves high nitrogen oxide reduction rates of 79% to 100% at low temperatures, even in the presence of moisture, surpassing conventional catalysts by maintaining high denitration efficiency and preventing sulfur oxide oxidation.
Implementation Method 1
the selective catalytic reduction reaction (NH3-SCR) with ammonia (NH3) as the reductant has been known
Implementation Method 2
since it oxidizes SO2 to SO3
Data Source
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AI summary
Provided is a combustion system in which a catalyst having superior denitration efficiency at a low temperature compared with those used in the conventional techniques is used in a selective catalytic reduction reaction using ammonia as a reducing agent. A combustion system equipped with: a combustion device for combusting a fuel; an exhaust passage through which an exhaust gas generated as the result of the combustion of the fuel in the combustion device can pass; a dust collection device which is arranged in the exhaust passage and can collect soot and dust in the exhaust gas; and a denitration device which is arranged in the exhaust passage and can remove a nitrogen oxide from the exhaust gas with a denitration catalyst. In the combustion system, the denitration device is arranged on the downstream side of the dust collection device in the exhaust passage, and the denitration catalyst is one which contains vanadium oxide as the main component and in which the content of a second metal in terms of oxide content is 1 to 40 wt% inclusive, wherein the second metal comprises at least one metal element selected from the group consisting of Co, W, Mo, Nb, Ce, Sn, Ni, Fe, Cu, Zn and Mn.