Polymetallic Oxide Tandem Catalyst for Propane Dehydrogenation
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Solution Overview
Problem
Traditional propylene production methods, such as light oil cracking and heavy oil catalytic cracking, face challenges like high energy consumption and carbon emissions, while propane dehydrogenation is limited by thermodynamic equilibrium, requiring ultra-high temperatures and inefficient heat transfer, leading to increased operating costs and catalyst deactivation.
Innovation Solution
A supported polymetallic oxide tandem catalyst is developed, coupling a direct propane dehydrogenation site with a selective hydrogen combustion site at the nano-scale, using metal vanadate MVO4 (M=Fe, Bi, or Mn) particles to shift reaction equilibrium and provide heat through hydrogen combustion, eliminating the need for external heating and reducing catalyst deactivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If external indirect heating mode is adopted for propane dehydrogenation, then the reaction can be sustained, but ultra-high temperature and low heat transfer efficiency are required
Solution Approach 1:
The patent combines the dehydrogenation reaction and hydrogen combustion reaction in a single reactor system with a tandem catalyst. The hydrogen combustion reaction provides direct internal heating to the dehydrogenation reaction, merging two previously separate processes into one integrated system that eliminates external heating requirements and improves heat transfer efficiency.
Solution Approach 2:
The patent converts the harmful effect of hydrogen (a byproduct that shifts equilibrium back to reactants) into a beneficial heat source through combustion. The hydrogen produced in the dehydrogenation reaction is subsequently combusted to provide the exact heat needed for the endothermic dehydrogenation reaction, turning a thermodynamic disadvantage into an energy advantage.
2Productivity
If high reaction temperature is used to improve equilibrium conversion, then propylene yield increases, but operating costs increase and catalyst deactivation accelerates
Solution Approach 1:
The patent converts the harmful effect of high temperature (which causes catalyst deactivation) into a beneficial effect by using hydrogen combustion to provide localized, controlled heating. The combustion reaction releases heat exactly where needed at the catalyst sites, allowing high conversion temperatures without the need for external heating systems that would require even higher temperatures and accelerate deactivation.
Solution Approach 2:
The system becomes self-heating through the coupling of dehydrogenation and hydrogen combustion reactions. The hydrogen produced in the dehydrogenation step is immediately combusted to provide the heat needed for the endothermic dehydrogenation reaction, creating a self-sustaining thermal system that eliminates external heating requirements and reduces operating costs.
3Use of energy by stationary object
If hydrogen combustion is used to provide heat, then direct heating is achieved, but oxygen co-feeding increases economic costs and safety hazards
Solution Approach 1:
The patent converts the potentially harmful combination of hydrogen and oxygen into a safe and beneficial process by using solid oxide fuel cell technology. The hydrogen from the dehydrogenation reaction reacts with oxygen from the air through the solid oxide fuel cell to generate electricity and heat, eliminating the need for direct hydrocarbon combustion and its associated safety hazards while maintaining high heating efficiency.
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
This approach achieves high single-pass conversion rates and selectivity for propylene, surpassing thermodynamic limits, reducing energy costs, and maintaining catalyst stability through self-heating and regeneration, while preventing oxygen co-feeding and deep oxidation product generation.
Implementation Method 1
the oxide of metal A serves as a direct dehydrogenation catalytic site
Implementation Method 2
the metal vanadate MVO4 (M=Fe, Bi, or Mn) nano-particles serve as the selective hydrogen combustion site
Implementation Method 3
the metal vanadate MVO4 (M=Fe, Bi, or Mn) nano-particles serve as the selective hydrogen combustion site
Implementation Method 4
This coupling mechanism shifts the reaction equilibrium to the right through the selective combustion of byproduct hydrogen
Implementation Method 5
the combustion of hydrogen releases chemical energy, and provides heat energy through direct heating
Data Source
AI summary
The present disclosure discloses a supported polymetallic oxide tandem catalyst, preparation method and application thereof, a surface of the support is supported with an oxide of metal A and then with metal vanadate nano-particles; and the oxide of metal A serves as a direct dehydrogenation catalytic site, and the metal vanadate nano-particles serve as a selective hydrogen combustion site. In the application of the tandem catalyst, dehydrogenation site and selective hydrogen combustion site are coupled at the nano-scale, and this coupling mechanism shifts the reaction equilibrium to the alkenes through the selective combustion of byproduct hydrogen, which effectively surpasses the thermodynamic limit; and meanwhile, the combustion of hydrogen releases chemical energy, and provides heat energy through direct heating, enabling the self-heating operation of the reaction. The present disclosure has the outstanding advantages of high single-pass conversion rate of light alkanes and high selectivity towards target product alkenes.