Fluidized Dehydrogenation Catalyst Regeneration via Oxygen Soak
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Solution Overview
Problem
Current propane dehydrogenation processes face challenges in increasing propylene yield without catalyst deactivation, as higher temperatures lead to rapid coke deposition and agglomeration of active phases, reducing catalyst activity and stability.
Innovation Solution
A process involving fluidized dehydrogenation catalyst particles for alkanes and alkyl aromatic hydrocarbons, including steps like combustion to remove coke, oxygen soaking to condition catalysts, and reduction to regenerate catalysts, maintaining activity and selectivity over multiple cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the temperature of the dehydrogenation process is increased to increase propylene yield, then the conversion increases, but the catalyst particles deactivate rapidly due to coke deposition and agglomeration
Solution Approach 1:
The patent implements periodic cycling between dehydrogenation mode (high temperature, propylene production) and combustion mode (coke removal, catalyst regeneration). The catalyst alternates between accumulating coke during dehydrogenation and being regenerated during combustion, enabling sustained high-temperature operation without permanent deactivation
Solution Approach 2:
The patent temporarily discards catalyst activity by allowing coke accumulation during dehydrogenation, then recovers the catalyst through combustion regeneration. This cyclical discarding and recovering of catalyst function allows the system to maintain high productivity while periodically restoring catalyst stability
2Object-generated harmful factors
If combustion is used to remove coke from catalyst particles, then coke is removed, but agglomeration of the active phase is exacerbated, rapidly reducing catalyst activity
Solution Approach 1:
The patent introduces a preliminary oxygen soak step before combustion where oxygen is adsorbed onto the catalyst at lower temperatures. This preliminary action prepares the catalyst for combustion by distributing oxygen uniformly, preventing localized overheating and agglomeration during the subsequent combustion phase
Solution Approach 2:
The patent uses oxygen as an intermediary substance that first adsorbs onto the catalyst surface during the oxygen soak phase, then gradually reacts during combustion. This intermediary approach allows controlled coke removal without direct high-temperature combustion that would cause agglomeration
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 process effectively increases propylene yield while maintaining catalyst activity and stability by regenerating catalysts through combustion and reduction steps, improving cycle longevity and efficiency.
Implementation Method 1
contacting a hydrocarbon-containing feed with fluidized dehydrogenation catalyst particles to effect dehydrogenation
Implementation Method 2
contacting at least a portion of the coked catalyst particles with an oxidant and a fuel in a combustion zone to effect combustion
Implementation Method 3
contacting at least a portion of the coked catalyst particles with an oxidant to effect combustion of at least a portion of the coke
Implementation Method 4
contacting at least a portion of the conditioned catalyst particles with a reducing gas in a reduction zone to produce regenerated catalyst particles
Implementation Method 5
contacting a hydrocarbon-containing feed with fluidized dehydrogenation catalyst particles
Data Source
AI summary
A hydrocarbon feed can be contacted with dehydrogenation catalyst particles to produce a conversion effluent that includes coked catalyst particles and dehydrogenated hydrocarbon(s). The coked catalyst particles can be contacted with an oxidant and a fuel to produce a combustion effluent that can include catalyst particles lean in coke and a combustion gas. The catalyst particles lean in coke can be contacted with an oxidative gas at an oxidizing temperature for a duration of at least 30 seconds to produce conditioned catalyst particles that can have an activity that can be less than the coked catalyst particles. The conditioned catalyst particles can be contacted with a reducing gas to produce regenerated catalyst particles that can have a dehydrogenation activity that can be greater than the coked catalyst particles. The dehydrogenated hydrocarbon(s) can be cooled, compressed, and a plurality of products can be separated from the compressed gaseous stream.