Halogenated Spent Catalyst Regeneration via Sequential Gas Treatment
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Solution Overview
Problem
Catalysts used in the aromatization or reforming process to convert non-aromatic hydrocarbons into aromatic compounds lose their activity and selectivity over time, leading to the need for effective regeneration methods to restore their performance.
Innovation Solution
A method involving the use of halogen-containing streams (chlorine and fluorine) followed by a decoking gas stream (oxygen) to treat spent aromatization catalysts, specifically those containing platinum on a KL-zeolite, to regenerate their activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spent aromatization catalysts are used beyond economic or operational thresholds, then production time is extended, but catalyst activity and selectivity deteriorate
Solution Approach 1:
The patent applies the discarding and recovering principle by developing a regeneration process that restores spent aromatization catalysts to their active state. The method involves treating the spent catalyst with a halogen-containing gas stream (comprising chlorine and fluorine) followed by a decoking gas stream (comprising oxygen), which removes carbonaceous deposits and restores catalytic activity, allowing the catalyst to be reused and extending production time without replacing the catalyst
2Reliability
If fresh catalyst is produced to replace spent catalyst, then catalyst activity is restored, but production cost increases
Solution Approach 1:
The patent recovers the value of spent catalysts by implementing a cost-effective regeneration process. Instead of discarding spent catalysts and purchasing expensive fresh catalysts, the method regenerates them in situ using gas stream treatment, significantly reducing the loss of substance associated with catalyst replacement and lowering overall production costs
3Reliability
If conventional regeneration methods are used, then catalyst is restored, but regeneration effectiveness is insufficient
Solution Approach 1:
The patent applies parameter changes by utilizing a specific sequence and composition of gas streams for regeneration. The method changes the chemical environment parameters by first introducing a halogen-containing gas stream (chlorine and fluorine) to modify the catalyst surface, then followed by an oxygen-containing decoking gas stream to remove carbonaceous deposits, achieving superior regeneration effectiveness compared to conventional single-step methods
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 method effectively rejuvenates the catalysts, restoring their activity to 50-80% of their fresh state, enhancing the selectivity and yield of aromatic compounds.
Implementation Method 1
contacting the spent catalyst with a halogen-containing stream comprising chlorine and fluorine to produce a halogenated spent catalyst
Implementation Method 2
contacting the halogenated spent catalyst with a decoking gas stream comprising oxygen
Data Source
AI summary
Methods for treating or rejuvenating a spent catalyst are disclosed. Such methods can employ a step of halogenating the spent catalyst, followed by decoking the halogenated spent catalyst. The halogenation step can utilize fluorine and chlorine together, or fluorine and chlorine can be applied sequentially.