Redox Catalyst for Oxidative Dehydrogenation of Alkyl Aromatics
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Solution Overview
Problem
Current dehydrogenation technologies for alkyl aromatic compounds, such as ethylbenzene to styrene, face challenges with high energy consumption, equilibrium limitations, and complex separation processes due to endothermic reactions and the need for steam co-feed, leading to inefficiencies and high carbon emissions.
Innovation Solution
The process involves using a redox catalyst with dehydrogenation and hydrogen selective combustion components, where lattice oxygen from the metal oxide catalyst selectively combusts hydrogen produced during dehydrogenation, reducing energy consumption and eliminating the need for steam co-feed by reintroducing an oxidant to re-oxidize the catalyst, allowing for repeated use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If steam co-feed is used in dehydrogenation process, then heat supply for endothermic reaction is improved, but energy consumption and carbon emissions increase
Solution Approach 1:
The patent converts the harmful byproduct hydrogen from dehydrogenation into a beneficial fuel source by selectively combusting it on the catalyst surface. The heat released from this exothermic hydrogen combustion provides the necessary thermal energy for the endothermic dehydrogenation reaction, eliminating the need for steam co-feed and reducing energy consumption.
Solution Approach 2:
The catalyst performs dual functions: catalyzing dehydrogenation and selectively combusting hydrogen. The hydrogen produced by dehydrogenation is immediately consumed by the same catalyst through selective combustion, creating a self-sufficient thermal system where the reaction's own byproduct fuels the reaction.
2Productivity
If gaseous oxygen is co-fed for selective hydrogen combustion, then hydrogen removal is improved, but safety concerns and air separation costs increase
Solution Approach 1:
The catalyst acts as an intermediary between hydrogen and oxygen. Instead of directly mixing hydrogen and oxygen gases (which creates safety hazards), the catalyst surface facilitates selective hydrogen combustion by providing active sites for hydrogen activation and reaction with lattice oxygen, mediating the interaction safely.
Solution Approach 2:
The patent uses lattice oxygen from the metal oxide catalyst for hydrogen combustion, which is then replenished by inexpensive air or oxygen. This eliminates the need for continuous co-feeding of gaseous oxygen, reducing safety risks while maintaining hydrogen removal efficiency. The oxidant can be introduced separately and cheaply.
3Temperature
If steam is co-fed as heat carrier and reaction atmosphere, then heat management is improved, but device complexity and separation requirements increase
Solution Approach 1:
The patent extracts the heat transfer function from steam and replaces it with the catalyst itself. The catalyst serves as both the reaction medium and heat source through exothermic hydrogen combustion, eliminating the need for steam as a separate heat carrier and simplifying the reaction system.
Solution Approach 2:
The metal oxide catalyst performs multiple functions simultaneously: catalyzing dehydrogenation, selectively combusting hydrogen, managing heat through exothermic reactions, and providing reaction atmosphere. This multi-functionality eliminates the need for separate steam co-feed systems and reduces overall system complexity.
4Productivity
If dehydrogenation reaction is performed, then alkyl aromatic conversion is improved, but equilibrium limitations reduce product yield
Solution Approach 1:
The patent converts the equilibrium limitation problem into an advantage by selectively removing hydrogen through combustion on the catalyst surface. This shifts the dehydrogenation equilibrium forward by continuously consuming the hydrogen byproduct, thereby increasing both conversion rate and product yield simultaneously.
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 enhances product selectivity and energy efficiency, reducing energy consumption and carbon emissions while maintaining high conversion rates and product yields, overcoming the limitations of existing technologies.
Implementation Method 1
introducing one or more dehydrogenation reactants to a metal oxide catalyst having dehydrogenation activity, and dehydrogenating the one or more dehydrogenation reactants
Implementation Method 2
selectively combusting the hydrogen released during dehydrogenation using a lattice oxygen from the metal oxide catalyst
Implementation Method 3
selectively combusting the hydrogen released during dehydrogenation using a lattice oxygen from the metal oxide catalyst, resulting in a reduced metal oxide catalyst and steam
Implementation Method 4
re-oxidizing the reduced metal oxide catalyst by introducing a gaseous oxidant to the reduced metal oxide catalyst
Data Source
AI summary
In one aspect, the disclosure relates to a process for dehydrogenating a first dehydrogenation reactant into its unsaturated counterparts. The disclosed process comprises introducing a dehydrogenation reactant to a metal oxide catalyst having dehydrogenation activity, and dehydrogenating the dehydrogenation reactant to provide its unsaturated counterpart and hydrogen; selectively combusting the hydrogen released during dehydrogenation using a lattice oxygen from the metal oxide catalyst, resulting in a reduced metal oxide catalyst and steam; re-oxidizing the reduced metal oxide catalyst by introducing a gaseous oxidant to the reduced metal oxide catalyst; and optionally re-using the re-oxidized metal oxide catalyst for catalytic conversion and combustion. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.