Mo-Bi-Fe-Co Catalyst for High Space Velocity Oxidation
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Solution Overview
Problem
Existing catalysts for producing unsaturated aldehydes from unsaturated lower olefins at high space velocity face issues such as diminished yield, lower activity, and hotspot accumulation due to heat generation, especially in non-off-gas-recirculating processes.
Innovation Solution
A Mo—Bi—Fe—Co based composite-metal-oxide catalyst is prepared through co-precipitation and rapid drying, with the addition of a diluting thermal conductor to enhance heat conductivity, allowing for high space velocity operations without hotspot accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If space velocity is increased to enhance productivity, then productivity is improved, but catalyst activity and yield diminish
Solution Approach 1:
The patent employs a composite catalyst system comprising Mo-Bi-Fe-Co composite metal oxide combined with thermal conductors (graphite, aluminum oxide, or silicon carbide). This composite structure enhances heat dissipation capacity while maintaining catalytic activity, enabling the catalyst to function effectively at high space velocities (120-200 hr⁻¹) without suffering from heat accumulation that would otherwise diminish catalyst activity and yield.
2Productivity
If space velocity is increased to enhance productivity, then productivity is improved, but hotspot accumulation occurs due to heat generation
Solution Approach 1:
The patent introduces thermal conductors (graphite, aluminum oxide, or silicon carbide) as intermediary materials mixed with the catalytic components. These thermal conductors act as heat transfer mediators that conduct away the heat generated during oxidation reactions, preventing hotspot formation and enabling high space velocity operation (120-200 hr⁻¹) without dangerous temperature accumulation.
3Ease of manufacture
If conventional catalyst preparation methods are used, then manufacturing simplicity is maintained, but catalyst performance at high space velocity is insufficient
Solution Approach 1:
The patent modifies the preparation parameters by controlling pH during co-precipitation (pH 1.5-3.0) and adjusting the mixing ratio of thermal conductors (10-50 wt%). These parameter changes create a catalyst with optimized pore structure and thermal conductivity, enabling it to achieve high space velocity capability (120-200 hr⁻¹) while maintaining ease of manufacture through conventional co-precipitation and extrusion techniques.
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 selectivity and yield of unsaturated aldehydes, with propylene conversion ratios exceeding 98% and carbon oxides yield below 3.3%, suitable for processes with or without off-gas recirculating at space velocities up to 200 hr−1(STP).
Implementation Method 1
partial oxidizing the olefins into aldehydes on an oxide catalyst containing molybdenum and bismuth
Implementation Method 2
partial oxidation of unsaturated lower olefin
Implementation Method 3
addition of a diluting thermal conductor to enhance heat conductivity
Implementation Method 4
A Mo—Bi—Fe—Co based composite-metal-oxide catalyst is prepared through co-precipitation and rapid drying
Data Source
AI summary
A method of preparing a catalyst for producing acrolein by oxidation of propylene at high space velocity, said catalyst is a Mo—Bi—Fe—Co based composite metal oxide. Producing unsaturated aldehyde via partial oxidation of lower unsaturated olefin at high space velocity using said catalyst is suitable for process with or without off-gas recirculating. Said catalyst is prepared by co-precipitation, the reaction conditions for using said catalyst to produce unsaturated aldehyde are, the space velocity of unsaturated lower olefin relative to catalyst being 120˜200 h-1(STP), reaction temperature being 300˜420° C. and absolute pressure being 0.1˜0.5 MPa; a single-stage unsaturated lower olefin conversion ratio of greater than 98.0% and carbon oxide yield of less than 3.3% with an overall yield of unsaturated lower aldehyde and acid of greater than 94.0% are obtained. The process to prepare the said catalyst is simple, easy to be repeated, and capable of industrial scale-up.