Cerium Oxide Cobalt Catalyst for N2O Decomposition
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Solution Overview
Problem
Current catalysts for decomposing nitrous oxide (N2O) in industrial processes face challenges such as high operating temperatures, sintering instability, and chemical reactions between support materials and active components, leading to deactivation, especially in the high-temperature range required for nitric acid production, where selective decomposition and thermal stability are crucial.
Innovation Solution
A catalyst system comprising a porous support of magnesium oxide or ceramic mixed oxide with a cerium oxide functional layer and an oxidic cobalt-containing layer, which prevents solid-state reactions and enhances selectivity and stability, allowing for effective N2O decomposition in both high-temperature and low-temperature industrial applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional catalysts are used for N2O decomposition in high-temperature industrial processes, then the decomposition reaction can proceed, but the catalyst suffers from sintering instability and chemical reactions between support materials and active components leading to deactivation
Solution Approach 1:
The patent employs a composite catalyst structure consisting of cobalt oxide active component supported on magnesium oxide or ceramic mixed oxide containing at least 50% magnesium oxide. This composite material configuration prevents solid-state reactions between the active component and support material while maintaining thermal stability at high operating temperatures (800-1000°C), thereby resolving the contradiction between achieving necessary operating temperature and maintaining catalyst reliability.
2Productivity
If the operating temperature is increased to achieve effective N2O decomposition, then the reaction efficiency improves, but the catalyst deactivation due to solid-state reactions increases
Solution Approach 1:
The magnesium oxide or ceramic mixed oxide support acts as an intermediary material that is chemically inert toward the cobalt oxide active component even at high temperatures. This intermediary support prevents harmful solid-state reactions while allowing the catalytic decomposition of N2O to proceed efficiently at elevated temperatures, thus maintaining both productivity and reliability.
3Object-affected harmful factors
If selective oxidation of ammonia is optimized to avoid N2O formation, then environmental protection is improved, but the process complexity and cost increase
Solution Approach 1:
Instead of modifying the primary ammonia oxidation process to prevent N2O formation (which would increase complexity), the patent extracts and treats the N2O component separately by introducing a dedicated decomposition catalyst in a subsequent stage. This approach removes the harmful N2O from the process stream without complicating the main production process, achieving environmental protection with minimal additional complexity.
4Object-affected harmful factors
If a catalyst is used for N2O decomposition downstream of absorption towers, then the greenhouse gas emissions are reduced, but the operating temperature is limited to lower ranges
Solution Approach 1:
The patent utilizes the parameter change of magnesium oxide's high melting point and chemical stability to enable catalyst operation at elevated temperatures (800-1000°C) that were previously unachievable with conventional supports. This parameter change in the support material's thermal properties expands the operating temperature range, allowing effective N2O decomposition both upstream and downstream of absorption towers while maintaining catalyst stability.
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 system provides long-term stability and high selectivity for N2O decomposition, reducing greenhouse gas emissions and operational costs, while being suitable for use in various industrial processes, including nitric acid production and adipic acid preparation.
Implementation Method 1
a porous support composed of polycrystalline or vitreous inorganic material comprising magnesium oxide or a ceramic mixed oxide
Implementation Method 2
a cerium oxide functional layer applied thereto
Implementation Method 3
a layer of oxidic cobalt-containing material applied thereto
Data Source
AI summary
Catalysts for the decomposition of N2O into nitrogen and oxygen in the gas phase, which comprises a porous support composed of polycrystalline or vitreous inorganic material, a cerium oxide functional layer applied thereto and a layer of oxidic cobalt-containing material applied thereto are described.The catalysts can be used, in particular, as secondary or tertiary catalysts in nitric acid plants.