Spent Catalyst Rejuvenation via Low-Temperature Impregnation
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Solution Overview
Problem
Hydrotreating catalysts used for gasoline desulfurization face challenges in maintaining selectivity and activity over time, leading to increased costs and environmental impact due to frequent replacement and variable performance quality.
Innovation Solution
A rejuvenation process for spent catalysts involving impregnation with metal precursors from group VIb and optional group VIII and phosphorus, followed by a drying stage at low temperatures, without the need for regeneration, to enhance selectivity and activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydrotreating catalyst is used for gasoline desulfurization, then sulfur content is reduced, but the catalyst activity decreases over time due to coke deposition and heteroelement compounds
Solution Approach 1:
The patent applies the discarding and recovering principle by collecting spent catalysts from various sources (regeneration units, storage silos, transport bags) and reactivating them through sulfidation treatment. This allows the catalyst to be recovered and reused multiple times, extending its service life while maintaining activity for sulfur removal applications.
Solution Approach 2:
The patent applies parameter changes by controlling the sulfidation process parameters (temperature, sulfurizing agent composition, treatment duration) to restore catalyst activity. By adjusting these parameters, the spent catalyst is transformed back to an active state suitable for hydrodesulfurization, effectively resetting its service life.
2Productivity
If catalyst replacement frequency is increased to maintain performance, then desulfurization efficiency is maintained, but costs and environmental impact increase
Solution Approach 1:
The patent implements a recovery system that captures spent catalysts before they are discarded, reactivates them through sulfidation, and returns them to service. This reduces catalyst consumption by extending the usable life of each catalyst batch, lowering both direct costs and environmental impact from catalyst disposal and manufacturing.
Solution Approach 2:
The patent enables the catalyst to serve itself by providing an in-situ or ex-situ reactivation process that restores its activity without requiring complete replacement. The sulfidation treatment allows the catalyst to self-renew its functional properties, reducing the need for external catalyst supply and disposal operations.
3Reliability
If selective hydrodesulfurization is performed to limit olefin hydrogenation, then octane number is maintained, but catalyst selectivity must be precisely controlled
Solution Approach 1:
The patent applies parameter changes by optimizing the sulfidation treatment conditions (temperature, sulfurizing agent, treatment time) to produce a catalyst with enhanced selectivity. The sulfidation process modifies the catalyst's chemical state and surface properties, enabling it to achieve high hydrodesulfurization activity while limiting olefin hydrogenation, thus maintaining octane number without requiring complex process control.
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 rejuvenation process improves the selectivity and maintains or minimizes the loss of hydrodesulfurizing activity, allowing for efficient desulfurization of gasolines with minimal reduction in octane number, reducing catalyst replacement frequency and associated costs.
Implementation Method 1
said at least partially spent catalyst is brought into contact with an impregnation solution containing a compound comprising a metal from group VIb
Implementation Method 2
a drying stage is carried out at a temperature of less than 200° C.
Data Source
AI summary
The invention relates to a process for the rejuvenation of an at least partially spent catalyst resulting from a hydrotreating process, said at least partially spent catalyst resulting from a fresh catalyst comprising a metal from group VIII, a metal from group VIb, an oxide support, and optionally phosphorus, said at least partially spent catalyst additionally comprising carbon in a content of between 2% and 20% by weight, with respect to the total weight of the at least partially spent catalyst, and sulfur in a content of between 1% and 8% by weight, with respect to the total weight of the at least partially spent catalyst, said process comprising the following stages:a) said spent catalyst is brought into contact with an impregnation solution containing a compound comprising a metal from group VIb,b) a drying stage is carried out at a temperature of less than 200° C.