Mixed Oxide Catalysts for Hydrotreatment
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Solution Overview
Problem
Current catalysts for hydrotreatment processes, particularly in hydrodesulfurization, hydrodenitrogenation, and hydrodearomatization, face challenges in achieving high activity and selectivity, especially with sterically hindered compounds like dibenzothiophenes and aromatic polynuclear compounds, and lack precise control over stoichiometry in their preparation.
Innovation Solution
Development of mixed oxides containing Ni, Mo, W, and optionally Si or Al, with a wolframite isostructural crystalline phase and an amorphous phase, which are sulfided to form catalysts with controlled crystallinity, enabling high catalytic performance in hydrotreatment processes, including hydrodesulfurization, hydrodenitrogenation, and hydrodearomatization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional catalysts are used for hydrotreatment, then basic catalytic function is provided, but activity and selectivity are insufficient for sterically hindered compounds
Solution Approach 1:
The patent applies parameter changes by controlling the crystallinity degree of the mixed oxide precursor within a specific range (5-50%) before sulfidation. This parameter control creates an optimal structure that enhances catalytic activity and selectivity for sterically hindered compounds like dibenzothiophenes and aromatic polynuclear compounds, resolving the insufficiency of conventional catalysts.
Solution Approach 2:
The patent uses composite materials by creating mixed oxides containing multiple transition metals (Ni, Mo, W) combined with alumina or silicoalumina supports. This composite structure provides synergistic effects that improve catalytic performance for difficult-to-treat compounds, addressing the limitation of single-metal catalysts.
2Ease of manufacture
If co-precipitation techniques are used for catalyst preparation, then catalyst formation is achieved, but precise control over stoichiometry is not possible
Solution Approach 1:
The patent applies preliminary action by preparing the mixed oxide precursor with controlled composition and crystallinity before the actual sulfidation step. This preliminary preparation ensures that the desired stoichiometry is achieved in the precursor, which then translates to precise compositional control in the final catalyst after sulfidation, overcoming the stoichiometry control limitations of direct co-precipitation 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 catalysts exhibit enhanced activity and selectivity in reducing sulfur, nitrogen, and aromatic compounds, particularly polynuclear aromatic compounds, while allowing for precise control over crystallinity, leading to improved performance in hydrotreatment processes.
Implementation Method 1
Sulfide metal catalysts, containing Ni, Mo, W, an element Z selected from Si, Al and mixtures thereof, may be obtained by the sulfidation of suitable precursors
Implementation Method 2
The catalysts obtained by the sulfidation of these precursors can be used as hydrotreatment catalysts, in particular as hydrodesulfurization, hydrodenitrogenation and/or hydrodearomatization catalysts
Implementation Method 3
The catalysts obtained by the sulfidation of these precursors can be used as hydrotreatment catalysts, in particular as hydrodesulfurization, hydrodenitrogenation and/or hydrodearomatization catalysts
Implementation Method 4
The catalysts obtained by the sulfidation of these precursors can be used as hydrotreatment catalysts, in particular as hydrodesulfurization, hydrodenitrogenation and/or hydrodearomatization catalysts
Data Source
Figure 1a
Figure 1b~1c
Figure 1d~1e
AI summary
New sulfide metal catalysts are described, containing Ni, Mo and W, an element Z selected from Si, Al and mixtures thereof, and possibly an organic residue, obtained by sulfidation of mixed oxide precursors, also new, characterized in that they comprise an amorphous phase and a wolframite isostructural crystalline phase, the crystallinity degree of said mixed oxides being higher than 0 and lower than 100%, preferably higher than 0 and lower than 70%. The catalysts of the invention are useful as hydrotreatment catalysts, and in particular as hydrodesulfurization, hydrodenitrogenation and/or hydrodearomatization catalysts.