Hydroprocessing Catalyst Rejuvenation via Acid Impregnation
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Solution Overview
Problem
Hydrotreating and hydrocracking catalysts become deactivated due to coke and sulfur compound accumulation, leading to reduced catalytic activity and necessitating frequent replacement, with regenerated catalysts exhibiting lower activity than fresh ones.
Innovation Solution
A rejuvenation process involving regeneration in an oxygen-containing gas stream, followed by contact with phosphoric acid and an organic acid with a pKa greater than 1.5, and a subsequent drying stage without calcination, to restore catalytic activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the catalyst is regenerated by gentle calcination to remove coke and sulfur compounds, then the catalyst can be reused and waste is reduced, but the catalytic activity is significantly reduced compared to fresh catalysts
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition of the catalyst through impregnation with phosphoric acid and organic acids after regeneration. This restores the catalytic activity by replenishing active species and modifying the surface properties of the catalyst, thereby resolving the contradiction between reusability and activity.
Solution Approach 2:
The patent uses phosphoric acid and organic acids as intermediary substances to restore the catalyst activity. These acids act as mediators that interact with the regenerated catalyst surface, replenishing active sites and enhancing the catalytic performance without requiring complete catalyst replacement.
2Productivity
If the catalyst is replaced frequently to maintain high activity, then the catalytic performance is maintained, but the cost and waste generation increase
Solution Approach 1:
By changing the chemical parameters of the spent catalyst through acid impregnation, the patent extends the catalyst lifecycle while maintaining activity. This approach reduces the frequency of catalyst replacement and minimizes waste generation.
Solution Approach 2:
The patent recovers value from spent catalysts by regenerating them through acid treatment, thereby extending their useful life. This prevents premature disposal of still-functional catalyst material and reduces overall catalyst consumption and waste.
3Ease of manufacture
If the regenerated catalyst is used directly without additional treatment, then the process is simple and cost-effective, but the hydrodesulfurizing activity is insufficient
Solution Approach 1:
The patent introduces a targeted chemical treatment step using phosphoric acid and organic acids to modify the catalyst properties. This relatively simple additional step effectively restores hydrodesulfurizing activity by replenishing active species and optimizing surface characteristics.
Solution Approach 2:
Phosphoric acid and organic acids serve as intermediary agents that bridge the gap between regenerated catalyst and fully active catalyst. These intermediaries facilitate the restoration of catalytic function through controlled chemical interactions.
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 recovers catalytic activity of spent catalysts to levels comparable to fresh catalysts, enabling efficient sulfur and nitrogen removal in hydrotreating and hydrocracking processes.
Implementation Method 1
the regenerated catalyst is brought into contact with phosphoric acid and an organic acid having each acidity constant pKa greater than 1.5
Implementation Method 2
a drying stage is carried out at a temperature of less than 200° C., without subsequently calcining it
Implementation Method 3
the at least partially spent catalyst is regenerated in an oxygen-containing gas stream at a temperature of between 300° C. and 550° C.
Data Source
AI summary
The invention concerns a method for rejuvenating an at least partially used catalyst originating from a hydroprocessing and/or hydrocracking process, the at least partially used catalyst being derived from a fresh catalyst comprising at least one group VIII metal (in particular, Co), at least one group VIB metal (in particular, Mo), an oxide support, and optionally phosphorus, the method comprising the steps: ⋅a) regenerating the at least partially used catalyst in a gas stream containing oxygen at a temperature between 300° C. and 550° C. so as to obtain a regenerated catalyst, ⋅b) then placing the regenerated catalyst in contact with phosphoric acid and an organic acid, each having acidity constant pKa greater than 1.5, ⋅c) performing a drying step at a temperature less than 200° C. without subsequently calcining it, so as to obtain a rejuvenated catalyst.