Dehydrogenation Catalyst with Solid Oxygen Carrier
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Solution Overview
Problem
Current dehydrogenation processes for alkanes and alkyl aromatic hydrocarbons face challenges such as equilibrium limitations, catalyst deactivation, and increased operating costs due to the need for reduced pressure, hydrocarbon feed dilution, and elevated temperatures, which also lead to undesirable side reactions and catalyst instability.
Innovation Solution
A process involving the use of a first catalyst with Pt supported on a specific metal oxide support and a second catalyst with Cr supported on another oxide, in conjunction with a solid oxygen carrier, to dehydrogenate hydrocarbons and combust molecular hydrogen, thereby shifting the equilibrium towards the desired dehydrogenated products and maintaining catalyst stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reduced operating pressure, hydrocarbon feed dilution, and increased operating temperature are employed to enhance equilibrium conversion, then dehydrogenation conversion is improved, but operating costs increase and undesirable side reactions are promoted
Solution Approach 1:
A solid oxygen carrier is introduced as an intermediary substance that selectively removes molecular hydrogen from the reaction mixture through oxidation. This mediator shifts the dehydrogenation equilibrium without requiring extreme operating conditions, thereby improving conversion while avoiding the high costs and side reactions associated with traditional methods
Solution Approach 2:
The invention changes the chemical environment by introducing oxygen-containing species that react with molecular hydrogen. This parameter change (adding oxygen) allows the system to achieve higher conversion at milder temperatures and pressures, reducing operating costs while maintaining productivity
2Productivity
If reduced operating pressure, hydrocarbon feed dilution, and increased operating temperature are employed to enhance equilibrium conversion, then dehydrogenation conversion is improved, but undesirable side reactions are promoted
Solution Approach 1:
The solid oxygen carrier acts as a selective intermediary that removes only molecular hydrogen through oxidation, leaving hydrocarbon species untouched. This selective removal shifts equilibrium without exposing hydrocarbons to the extreme conditions that cause cracking, coking, and other undesirable side reactions
Solution Approach 2:
By changing the chemical composition through oxygen introduction, the system achieves equilibrium shift at milder conditions, thereby suppressing side reactions that occur at high temperatures and pressures
3Reliability
If frequent regeneration of the catalyst system using oxygen-containing gas is performed to replenish lattice oxygen in the solid oxygen carrier, then solid oxygen carrier activity is maintained, but catalyst stability is challenged
Solution Approach 1:
The catalyst system is segmented into two functionally independent components: the dehydrogenation catalyst and the solid oxygen carrier. This segmentation allows each component to be optimized and regenerated separately, with the catalyst exposed to mild regeneration conditions that preserve its stability while the oxygen carrier undergoes frequent oxidation cycles
4Productivity
If the dehydrogenation catalyst is exposed to pre-reduction step with molecular hydrogen, then catalyst activity is enhanced, but lattice oxygen is stripped from the solid oxygen carrier
Solution Approach 1:
By segmenting the catalyst system into separate functional components, the dehydrogenation catalyst can undergo pre-reduction for activity enhancement without affecting the solid oxygen carrier's lattice oxygen content, as each component operates and regenerates independently
Solution Approach 2:
The segmented structure acts as a protective intermediary, isolating the solid oxygen carrier from reducing conditions that would otherwise strip its lattice oxygen, while still allowing the catalyst to receive beneficial pre-reduction treatment
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 process enhances the selectivity and conversion of hydrocarbons to dehydrogenated products while minimizing catalyst deactivation and operating costs, maintaining high activity over multiple cycles.
Implementation Method 1
contacting the hydrocarbon-containing feed with a first catalyst that can include Pt disposed on a first support or a second catalyst that can include Cr disposed on a second support within the conversion zone to effect dehydrogenation
Implementation Method 2
contacting the effluent with a solid oxygen carrier disposed within the conversion zone to effect combustion of at least a portion of the molecular hydrogen
Implementation Method 3
Molecular hydrogen that is produced during the processes can then be combusted via the lattice oxygen in the solid oxygen carrier
Data Source
AI summary
Processes for converting an alkane to an alkene. In some embodiments, the process can include contacting a hydrocarbon-containing feed with a first catalyst that can include Pt or a second catalyst that can include Cr within a conversion zone to effect dehydrogenation of at least a portion of the hydrocarbon-containing feed to produce an effluent that can include one or more dehydrogenated hydrocarbons and molecular hydrogen. The process can also include contacting the effluent with a solid oxygen carrier disposed within the conversion zone to effect combustion of at least a portion of the molecular hydrogen to produce a conversion product that can include the one or more dehydrogenated hydrocarbons and water. In some embodiments, contacting the feed with the first or second catalyst can occur in a first conversion zone and contacting the effluent with the solid oxygen carrier can occur in a second conversion zone.