Modified Solid Oxygen Carrier for Selective Hydrogen Combustion
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Solution Overview
Problem
Conventional solid oxygen carriers for hydrogen combustion in hydrocarbon environments suffer from low selectivity, high cost, and limited regenerability, leading to inefficient hydrogen combustion and unwanted hydrocarbon combustion.
Innovation Solution
A solid oxygen carrier comprising 10 wt% or more of a first row transition metal oxide with multiple redox states, modified with alkali metal oxides or alkali metal halides, such as potassium oxide and chloride, to enhance hydrogen combustion selectivity and regenerability, while minimizing hydrocarbon combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional metal oxides are used as solid oxygen carriers for hydrogen combustion, then hydrogen combustion activity is achieved, but combustion selectivity (H2 vs. hydrocarbon) is low
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the core metal oxide (e.g., CuO, Fe2O3, Mn3O4) provides hydrogen combustion activity while the shell layer (e.g., Al2O3, SiO2, TiO2) provides selectivity by preventing hydrocarbon contact with the active sites. This spatial differentiation of functions resolves the contradiction between combustion activity and selectivity.
Solution Approach 2:
The patent uses composite materials by combining core metal oxide particles with shell materials to create a composite solid oxygen carrier. The core-shell composite structure integrates the high hydrogen combustion activity of transition metal oxides with the high selectivity and stability of oxide shells, simultaneously achieving both combustion activity and selectivity.
2Duration of action of stationary object
If conventional metal oxides are used as solid oxygen carriers, then hydrogen combustion can occur, but regenerability is low
Solution Approach 1:
The patent applies parameter changes by optimizing the oxidation-reduction cycling parameters of the metal oxide. The core metal oxide is designed to undergo reversible redox transitions (e.g., CuO ↔ Cu, Fe2O3 ↔ Fe3O4) at controlled temperatures, allowing repeated regeneration cycles while maintaining combustion activity. The shell material parameters are also optimized to withstand thermal cycling.
3Productivity
If conventional metal oxides are used as solid oxygen carriers, then hydrogen combustion activity is achieved, but cost is high
Solution Approach 1:
The patent applies this principle by using abundant, low-cost transition metal oxides (CuO, Fe2O3, Mn3O4) as the core material instead of expensive noble metal catalysts. These earth-abundant materials provide sufficient combustion activity at much lower cost, making the solid oxygen carrier economically viable for industrial applications.
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 modified solid oxygen carrier achieves high selectivity for hydrogen combustion, increased oxygen storage capacity, and improved regenerability, leading to enhanced yield and reduced coke formation in processes like propane dehydrogenation.
Implementation Method 1
a first row transition metal oxide comprising multiple redox states... H2 that is produced during the processes may be combusted through the lattice oxygen in the metal oxides that have multiple redox states
Implementation Method 2
metal oxide with multiple redox states that can also release lattice oxygen at the relevant reaction conditions
Implementation Method 3
one or more alkali metal salts comprising at least one of an alkali metal oxide and an alkali metal halide... enhance hydrogen combustion selectivity
Data Source
AI summary
Metal oxides are provided that have selective hydrogen combustion activity while also acting as solid oxygen carriers (SOCs). The metal oxides correspond to a metal oxide core of at least one metal having multiple oxidation states that is modified with an alkali metal oxide and/or alkali metal halogen (such as an alkali metal chloride). The resulting modified metal oxide, corresponding to a solid oxygen carrier, can allow for selective combustion of hydrogen while reducing or minimizing combustion of hydrocarbons, such as within a propane dehydrogenation environment. Additionally, it has been unexpectedly found that modifying the core metal oxide with the alkali metal oxide and/or alkali metal chloride can also mitigate coke formation on the solid oxygen carrier. Methods of using such metal oxides for selective hydrogen combustion are also provided.