Hydrogenation Catalyst Regeneration via Stepwise Air Addition
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Solution Overview
Problem
Existing catalyst regeneration processes for hydrogenation of aromatic species are inefficient, particularly when substances other than water are deposited on the catalyst, leading to reduced activity and increased energy consumption due to high temperatures.
Innovation Solution
A process involving purging with nitrogen at 50-100°C, followed by stepwise addition of air to achieve a 10-90% air volume ratio, and subsequent reduction of nitrogen flow to maintain temperatures similar to the hydrogenation process, effectively regenerating catalysts without excessive oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the catalyst is calcined at high temperatures (>200°C) under air to remove deposits, then the deposits are removed effectively, but energy consumption increases and the catalyst may be damaged
Solution Approach 1:
The invention changes the temperature parameter from high (>200°C) to low (50-100°C) during regeneration, using a stepped air addition approach that allows effective deposit removal without calcination temperatures, thus reducing energy consumption while maintaining catalyst activity
Solution Approach 2:
The invention performs preliminary purging with inert gas at elevated temperature (50-100°C) before introducing air, which prepares the catalyst surface and allows subsequent air addition at lower temperatures to be effective, preventing the need for high-temperature calcination
2Reliability
If air is introduced directly to the catalyst to remove deposits, then the regenerating action is enhanced, but temperature rises excessively which can damage the catalyst or reactor
Solution Approach 1:
The invention introduces preliminary purging with inert gas at 50-100°C before air addition, which prepares the catalyst surface and establishes a controlled atmosphere that allows subsequent air introduction without excessive temperature rises
Solution Approach 2:
The air addition is segmented into multiple steps with increasing air proportions (10-30-50-70-90%), allowing gradual oxidation that prevents excessive temperature rises while effectively removing deposits over time
Solution Approach 3:
The inert gas purging phase acts as a cushioning step before air introduction, stabilizing the system at 50-100°C and creating a controlled transition environment that prevents thermal shock and excessive temperature rises during air addition
3Reliability
If the catalyst is purged with inert gas until activity is regained, then water is removed effectively, but other substances that lower hydrogenation activity remain on the catalyst
Solution Approach 1:
The invention changes the chemical composition parameter by introducing air (oxygen) in stepped proportions after inert gas purging, enabling oxidation-based removal of organic deposits and other substances that inert gas purging alone cannot remove
Solution Approach 2:
The invention converts the potentially harmful oxygen in air into a beneficial regenerating agent by controlling its introduction in small stepped proportions, allowing oxygen to oxidize and remove organic deposits and other substances without causing excessive temperature rises or catalyst damage
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 method rapidly and effectively improves catalyst activity, preventing temperature rises that could damage the catalyst or reactor, allowing for more efficient hydrogenation with increased conversions and prolonged catalyst life.
Implementation Method 1
the catalyst is purged with an inert gas until the catalyst has partly or even completely regained its activity. A reason given for the regenerating action described with reference to benzene hydrogenation is the removal of water, i.e. the drying of the catalyst.
Implementation Method 2
It is possible here to calcine the catalyst, in which the deposits are removed at high temperatures (>200° C.) under air
Implementation Method 3
Catalysts can alternatively be regenerated by passing a gas stream over them, by which the deposits are entrained and hence removed.
Data Source
AI summary
The invention provides a process for regenerating a catalyst used for the hydrogenation of an aromatic species, consisting of several steps. First the system is purged with nitrogen, then air is metered in stepwise, and the addition of nitrogen is subsequently ended until only air is present.