Molybdenum-Bismuth-Cobalt Catalyst Crystallinity Optimization
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Solution Overview
Problem
Current methods for producing unsaturated aldehydes, unsaturated carboxylic acids, and conjugated dienes from propylene, isobutylene, or t-butyl alcohol face challenges in achieving high yield and catalytic activity, leading to increased production costs and reduced catalyst lifespan due to thermal stress, with unclear relationships between catalyst physical properties and longevity.
Innovation Solution
A catalyst composition comprising molybdenum, bismuth, and cobalt, with specific X-ray diffraction peak intensity ratios and multi-layer filling methods, where the composition ratio of Bi is increased from the gas inlet to the outlet in the reaction tube, optimizing peak intensities and pore volumes to enhance catalytic activity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a catalyst with high catalytic activity is used to improve yield, then the reaction temperature must be increased, but this increases thermal stress on the catalyst and reduces its lifespan
Solution Approach 1:
The patent changes the physical and chemical parameters of the catalyst by controlling the crystallinity of the active component within a specific range (4-18% as measured by XRD). This parameter optimization allows the catalyst to achieve high activity at lower temperatures, resolving the contradiction between productivity and catalyst lifespan.
Solution Approach 2:
The patent uses a composite catalyst system containing multiple metal oxides (Bi2Mo2O9 and CoMoO4) with specific phase ratios. This composite structure provides both high catalytic activity and thermal stability, enabling the catalyst to maintain performance under thermal stress while achieving high yield.
2Temperature
If the salt bath temperature is increased to maintain yield when using a low-activity catalyst, then the catalytic activity improves, but the selectivity and yield are reduced due to thermal stress
Solution Approach 1:
By optimizing the crystallinity parameter of the catalyst active component to within 4-18%, the patent enables the catalyst to achieve high activity at lower temperatures. This eliminates the need to increase salt bath temperature, thereby preventing thermal stress-induced reduction in selectivity and yield.
Solution Approach 2:
The patent performs preliminary optimization of catalyst crystallinity and phase composition before the reaction occurs. This pre-preparation ensures the catalyst has the optimal structure to operate efficiently at lower temperatures, preventing the need for temperature increases that would harm selectivity and yield.
3Stability of the object's composition
If two or more layers of catalysts with different activities are filled to reduce hot spot temperature and improve stability, then the reaction stability improves, but the device complexity increases
Solution Approach 1:
The patent applies local quality by creating a multi-layer catalyst filling structure where each layer has different physical and chemical properties. The first layer (closer to inlet) and second layer (closer to outlet) have different crystallinity ranges and phase ratios, allowing each layer to perform optimally for its specific position, thus improving reaction stability while managing complexity through functional differentiation.
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 proposed solution significantly improves catalytic activity and yield while maintaining long-term operational stability and reducing production costs by optimizing catalyst composition and layering, thereby extending catalyst lifespan and maintaining high selectivity.
Implementation Method 1
a sum (S) of ratios of peak intensities at 2θ = 14.1° ± 0.1°, 25.4° ± 0.1°, and 28.5° ± 0.1° to a peak intensity at 2θ = 26.5° ± 0.1° in an X-ray diffraction pattern obtained by using CuKα rays as an X-ray source
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A catalyst containing, as an essential component, molybdenum; bismuth; and cobalt, in which a sum (S) of ratios of peak intensities expressed by the following formula in an X-ray diffraction pattern obtained by using CuKα rays as an X-ray source is 42 or more and 113 or less. S=peakintensityat2θ=14.1°±0.1°+peakintensityat2θ=25.4°±0.1°+peakintensityat2θ=28.5°±0.1°/peakintensityat2θ=26.5°±0.1°×100