Chromium-Free Catalyst for NOx Removal
Solution Overview
Problem
Conventional catalysts for nitrogen oxide removal in exhaust gases with high nitrogen dioxide to nitrogen oxides ratios are inefficient and contain chromium, posing environmental concerns.
Innovation Solution
A chromium-free catalyst comprising titanium, tungsten, and vanadium oxides, with manganese or copper oxides, that is prepared by impregnation or kneading with a solvent and firing, effectively reducing nitrogen oxides to harmless nitrogen and water even when nitrogen dioxide levels are high.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional catalysts containing chromium are used, then denitration performance for high NO2 exhaust gas is improved, but environmental safety deteriorates due to chromium contamination
Solution Approach 1:
The invention extracts and removes chromium from the catalyst composition entirely. The patent develops a chromium-free catalyst system using alternative metal oxides (manganese, copper, zinc, or aluminum) combined with tungsten oxide and vanadium oxide on a titania carrier, thereby eliminating chromium contamination while maintaining denitration performance for high NO2 exhaust gas
Solution Approach 2:
The invention changes the chemical composition parameters of the catalyst by substituting chromium with other metal oxides. Specifically, it uses manganese oxide, copper oxide, zinc oxide, or aluminum oxide in combination with tungsten oxide and vanadium oxide, altering the catalyst's chemical properties to achieve both chromium-free status and effective denitration performance
2Reliability
If conventional catalysts are used for high NO2 exhaust gas, then they show sufficient denitration performance, but the proportion of NO2 reduces the effectiveness of standard catalysts
Solution Approach 1:
The invention employs composite materials by combining multiple metal oxides (manganese oxide, copper oxide, zinc oxide, or aluminum oxide) with tungsten oxide and vanadium oxide on a titania carrier. This composite structure creates synergistic effects that enable the catalyst to maintain high denitration performance specifically under high NO2 conditions where conventional single-component catalysts fail
Solution Approach 2:
The invention copies and adapts the successful denitration mechanism from chromium-based catalysts by using alternative metal oxides that replicate the functional properties. The manganese, copper, zinc, or aluminum oxides combined with tungsten and vanadium oxides reproduce the catalytic activity needed for high NO2 environments without relying on chromium
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 denitration performance without chromium, efficiently decomposing nitrogen oxides into nitrogen and water, even in exhaust gases with high nitrogen dioxide concentrations, ensuring effective treatment and environmental safety.
Implementation Method 1
a catalyst for nitrogen oxide removal which catalytically reduces nitrogen oxides in an exhaust gas in the presence of ammonia
Implementation Method 2
nitrogen oxides can be decomposed into harmless nitrogen and water upon reduction
Implementation Method 3
prepared by impregnating a base material comprising the first component with the second component and carrying the second component on the base material
Implementation Method 4
drying, and then firing the base material impregnated with and bearing the second component
Data Source
AI summary
A catalyst for nitrogen oxide removal, which catalytically reduces nitrogen oxides in an exhaust gas in the presence of ammonia, comprises: a first component comprising an oxide of titanium, an oxide of tungsten, and an oxide of vanadium; and a second component comprising an oxide of manganese, or an oxide of manganese and an oxide of copper.