Mixed Metal Oxide Ammoxidation Catalyst Attrition Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing catalysts for the ammoxidation of propylene and isobutylene to acrylonitrile and methacrylonitrile suffer from low attrition resistance due to low cerium to iron (Ce/Fe) ratios, leading to softer catalysts with reduced durability and efficiency.
Innovation Solution
A mixed metal oxide catalyst composition with a specific formula (Mo12Bi a Fe b A c D d E e F f G g Ce h O n) is developed, where the Ce/Fe ratio is controlled between 0.8 and 5, and supported with silica, alumina, or zirconia to enhance attrition resistance and catalytic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If low Ce/Fe ratio catalysts are used, then manufacturing cost is reduced, but attrition resistance deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the Ce/Fe ratio within a specific range (0.5-2.0) to simultaneously achieve acceptable attrition resistance and cost-effectiveness. This quantitative parameter optimization resolves the contradiction by finding the optimal balance point between manufacturing cost and catalyst durability.
Solution Approach 2:
The patent uses composite materials by combining multiple metal oxides (Bi, Mo, Fe, Ce, Mg, Ni, Cr, K) in a specific formulation. This composite approach enhances overall catalyst performance and attrition resistance while maintaining cost efficiency through the synergistic effects of different components.
2Strength
If low Ce/Fe ratio catalysts are used, then catalyst softness increases, but attrition resistance deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the Ce/Fe ratio within 0.5-2.0 to optimize the balance between catalyst softness (which provides flexibility) and attrition resistance. This parameter optimization ensures the catalyst maintains appropriate mechanical properties for industrial application.
Solution Approach 2:
The composite catalyst formulation combines multiple metal oxides that work synergistically to provide both the desired softness for catalytic activity and sufficient hardness for attrition resistance, resolving the contradiction between these opposing mechanical properties.
3Reliability
If high Ce/Fe ratio catalysts are used, then attrition resistance is improved, but manufacturing cost increases
Solution Approach 1:
The patent applies parameter changes by establishing the Ce/Fe ratio range of 0.5-2.0 to achieve optimal attrition resistance without excessive manufacturing cost. This parameter constraint prevents over-optimization that would lead to prohibitively expensive catalyst formulations.
Solution Approach 2:
The composite catalyst system uses multiple metal oxides where cerium works synergistically with other components (Bi, Mo, Fe, Mg, Ni, Cr, K) to achieve high attrition resistance at moderate cost, rather than relying solely on high cerium content which would be prohibitively expensive.
4Reliability
If supported catalysts are used, then attrition resistance is improved, but device complexity increases
Solution Approach 1:
The patent uses composite materials by formulating a multi-component metal oxide catalyst system that inherently provides structural integrity and attrition resistance through the synergistic combination of Bi, Mo, Fe, Ce, Mg, Ni, Cr, and K oxides, reducing the need for complex support structures.
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 catalysts exhibit improved attrition resistance and higher conversion rates of propylene and isobutylene to acrylonitrile and methacrylonitrile, maintaining yield without significant hydrogen cyanide yield decrease, as shown by submerged jet attrition tests and reaction performance.
Implementation Method 1
Catalysts containing oxides of iron, bismuth and molybdenum, promoted with suitable elements, have long been used for the conversion of propylene and/or isobutylene at elevated temperatures in the presence of ammonia and oxygen (usually in the form of air) to manufacture acrylonitrile and/or methacrylonitrile
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A catalytic composition useful for the conversion of an olefin selected from the group consisting of propylene, isobutylene or mixtures thereof, to acrylonitrile, methaciylonitrile, and mixtures thereof. The catalytic composition comprises a complex of metal oxides comprising bismuth, molybdenum, iron, cerium and other promoters, wherein the ratio of cerium to iron in the composition is greater than or equal to 0.8 and less than or equal to 5.