Heterogeneous Catalyst Noble Metal Shell Distribution
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Solution Overview
Problem
Existing heterogeneous catalysts with noble metals concentrated in an outer region face inefficiencies in larger particle sizes and distribution, particularly in processes like methyl methacrylate production from methacrolein and methanol, where noble metal concentration near the surface is not adequately optimized.
Innovation Solution
A heterogeneous catalyst with an average diameter of at least 200 microns, where at least 90 wt % of the noble metal is concentrated in the outer 50% of the catalyst volume, utilizing refractory oxides like alumina as support and noble metals such as gold or palladium, ensuring high surface area and specific distribution to enhance catalytic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If larger catalyst particles are used, then catalyst stability and reduced pressure drop are improved, but noble metal distribution and catalytic efficiency deteriorate
Solution Approach 1:
The patent applies local quality by concentrating noble metals specifically in the outer shell region (within 50 microns from the surface) of larger catalyst particles (200-3000 microns), rather than uniform distribution. This creates zones of different functionality: the outer shell provides high catalytic activity where reactants first contact, while the inner core provides structural stability and reduces pressure drop, resolving the contradiction between particle size and catalytic efficiency.
2Productivity
If noble metals are concentrated in the outer region, then catalytic activity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs preliminary action by pre-forming support particles with controlled pore structures and surface areas before impregnating them with noble metals. This pre-preparation of the support matrix with specific physical properties (surface area 1-500 m²/g, pore volume 0.01-1.0 mL/g) allows subsequent noble metal deposition to occur preferentially in outer regions, achieving the desired concentration profile without complex post-processing steps.
3Productivity
If higher noble metal concentration near surface is achieved, then space-time yield is improved, but noble metal usage cost increases
Solution Approach 1:
The patent optimizes noble metal utilization by concentrating it locally in the outer shell region where catalytic reactions occur, rather than distributing it uniformly throughout the particle. This local concentration strategy (at least 50 wt% of noble metal within outer 50 microns) ensures that expensive noble metals are positioned where they provide maximum catalytic benefit, improving space-time yield while minimizing total noble metal content required.
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 superior space-time yield and reduced byproduct formation, particularly at low oxygen levels, demonstrating improved catalytic efficiency and stability in methyl methacrylate production processes.
Implementation Method 1
The catalyst is especially useful in a process for preparing methyl methacrylate from methacrolein and methanol
Data Source
AI summary
A heterogeneous catalyst comprising a support and a noble metal. The catalyst has an average diameter of at least 200 microns and at least 90 wt % of the noble metal is in the outer 50% of catalyst volume.